Working system for substrate

ABSTRACT

A working system for a circuit substrate enabling a control of stopping the substrate without inconvenience. A PWB detector  308  held by a Y-axis slide  252  of an XY robot  266  moving a component mounting head, has reflection type photoelectric sensors  310, 312  spaced from each other in a direction of conveyance of a PWB  12  by a conveyor  14.  When the PWB  12  carried in the system, the sensors  310, 312  are moved to a position corresponding to a downstream-side edge of the PWB  12  stopped at a predetermined stop position. The PWB  12  is decelerated when detected by one of the sensors on the upstream side, and stopped at a desired position regardless of its shape, dimensions and conveying direction, when detected by the other or downstream sensor. Electronic circuit components 16 can be supplied to plural kinds of PWBs  12  with one component supply device.

TECHNICAL FIELD

The present invention relates to a working system for a circuitsubstrate, in particular, to a control of stopping a circuit substrateconveyed by a substrate conveyor.

BACKGROUND ART

A working system for a circuit substrate is a system for performing apredetermined operation for a circuit substrate, and is, for example, anelectronic-circuit-component mounting system for mounting electroniccircuit components as components of an electronic circuit on aprinted-wiring board, or a highly-viscous fluid coating system forcoating a printed-wiring board with a highly viscous fluid such as anadhesive. As one kind of such a working system for a circuit substrate,there is known a system comprising: (a) a substrate conveyor capable ofconveying a circuit substrate along a straight line in a conveyingdirection, and of stopping the circuit substrate at a desired positionin the conveying direction; (b) a moving apparatus having a firstmovable member which is movable in the conveying direction and a secondmovable member which is movable in a direction intersecting with theconveying direction, the moving apparatus being capable of moving thesecond movable member to a desired location in a plane; and (c) aworking head which is held by the second movable member and performs aplurality of operations for prescribed points on the circuit substratestopped as indicated above. In such a type of system, the circuitsubstrate is conveyed by the substrate conveyor and stopped at aposition where to perform the operation.

Therefore, the conventional system has at least one of a stopper and asensor for stopping the circuit substrate. The stopper is moved by themoving apparatus to its operative position located in a path ofconveyance along which the circuit substrate is conveyed, and to itsinoperative position away from the path of conveyance. When the circuitsubstrate is carried into the working system, the stopper is located atthe operative position to be brought into contact with the circuitsubstrate to stop the circuit substrate. For example, the sensorconsists of two pairs of sensors which pairs are spaced from each otherin the conveying direction, and is adapted such that the conveyance ofthe circuit substrate is decelerated when one of the two pairs ofsensors located on the upstream side in the conveying direction detectsthe circuit substrate, and the circuit substrate is stopped when theother pair of sensors located downstream detects the circuit substrate.

Such a stopper or sensor is disposed in a main body of the workingsystem, at a fixed position in most cases, and the circuit substrate isstopped at a stop position in relation to a predetermined position of acontact portion, or of a detection portion which is to be detected bythe sensor. The stopper or sensor may be disposed such that its locationin the conveying direction in which the circuit substrate is conveyed isadjustable, and an operator adjusts the location of the stopper orsensor so that the circuit substrate is stopped at an appropriateposition.

DISCLOSURE OF THE INVENTION

However, whether disposed with the location fixed or adjustable, theconventional stopper or sensor suffers from an inconvenience as follows.In the case where the location is fixed, it is typical that an edge onthe downstream side of a circuit substrate acts as the contact portionor detection portion, and the stopper or sensor is located at a positionwhich is suitable for performing an operation on a circuit substrate ofa relatively large size. In such an arrangement, however, when thecircuit substrate carried into the working system is a relativelysmall-sized circuit substrate, the circuit substrate is stopped in amarginal part of a range of movement of the working head (i.e., in anedge portion on the downstream side of the range), leading to manydrawbacks which will be described later. Although the stopper or sensormay be disposed such that the stopper or sensor is adjustable inlocation to avoid drawbacks which would be encountered in the case wherethe stopper or sensor is disposed with its location fixed, it isbothersome for the operator to adjust the location of the stopper orsensor. Further, in a case where it is so arranged that the circuitsubstrate is supported from the under side by a substrate supportingdevice while the operation is performed on the circuit substrate, afreedom in selecting the location to dispose the substrate supportingdevice might be limited. More specifically described, in most cases, thestopper or sensor is positioned under a plane on which the circuitsubstrate is conveyed so as not to obstruct the operation of the workinghead and a supporting member for supporting the circuit substrate cannot be disposed in a spatial range within which the stopper or sensor ismoved for adjusting its location.

It is therefore an object of this invention to make the working systemfor the circuit substrate capable of controlling the stop of the circuitsubstrate while avoiding the above-described drawbacks. This object maybe achieved according to any one of the following modes of the inventionin the form of a working system for a circuit substrate, each of whichis numbered like the appended claims and depends from the other mode ormodes, where appropriate, for easy understanding of the invention. It isto be understood that the present invention is not limited to thetechnical features of the following modes or any combinations thereof.It is to be further understood that a plurality of features included inany one of the following modes of the invention are not necessarilyprovided all together, and that the invention may be embodied with onlyselected one or ones of the features described with respect to the samemode.

(1) A working system for a circuit substrate, comprising:

-   -   a substrate conveyor which conveys a circuit substrate in a        conveying direction along a straight line, and is capable of        stopping the circuit substrate at a desired position in the        conveying direction;    -   a moving apparatus having a first movable member which is        movable in one of a first direction and a second direction which        intersect with each other in a plane parallel to a surface of        the circuit substrate which has been conveyed by the substrate        conveyor and then stopped, and a second movable member which is        held by the first movable member such that the second movable        member is movable in the other of the first direction and the        second direction, the moving apparatus moving the second movable        member to a desired location in the plane;    -   a working head which is held by the second movable member and        performs a plurality of operations for prescribed points on the        circuit substrate which has been stopped;    -   a substrate detector which is held by one of the first movable        member and the second movable member which is movable at least        in the conveying direction, and detects a detection portion of        the circuit substrate, which detection portion is predetermined        as an object to be detected by the substrate detector while the        circuit substrate is conveyed by the substrate conveyor; and    -   a substrate stop position controller which controls the moving        apparatus to move the substrate detector to a predetermined        location, and controls the substrate conveyor based on a result        of a detection of the detection portion by the substrate        detector positioned at the predetermined location, so as to        control a stop position at which the circuit substrate is        stopped.

The predetermined detection portion may be the circuit substrate itself,or may be a part exclusively provided for the purpose of the detection.In the former case, the predetermined detection portion may be an edgeof the circuit substrate which edge is on the downstream side in theconveying direction, a wiring pattern on an insulating substrate of thecircuit substrate, or a positioning hole for positioning the circuitsubstrate.

The substrate detector may be of non-contact type, as described belowwith respect to mode (2), or of contact type. For instance, thecontact-type substrate detector consists of a limit switch or a touchsensor, a terminal of which is brought into contact with the circuitsubstrate and is thereby moved, so that a detection signal indicative ofthat the circuit substrate has been detected is output.

The working system for the circuit substrate may be theelectronic-circuit-component mounting system, or a highly-viscous fluidcoating system for coating the circuit substrate with a highly viscousfluid such as an adhesive, as described above. As the highly-viscousfluid coating system, there are known an ejection application system inwhich a highly-viscous fluid is ejected from a discharge nozzle to beapplied in the form of spots onto the circuit substrate, and a screenprinting system in which a solder cream or other materials isscreen-printed on the circuit substrate through a screen mask.

The circuit substrate may be: a printed wiring board comprising aninsulating substrate and a printed wiring on the insulating substrate,with no electronic circuit components mounted yet on the printed wiring;a printed wiring board with part of electronic circuit componentsmounted on a printed wiring; and a printed circuit board whereelectronic circuit components have been mounted on and soldered to aprinted wiring to complete interconnections therebetween.

The first and second movable members are respectively movable in one andthe other of the first and second directions which intersect each other,so that the second movable member is movable to the desired location inthe plane parallel to the surface of the circuit substrate. It is notessential, but preferable, that the first and second directions areperpendicular to each other. For example, the first movable member ismovable in a direction parallel to the conveying direction of thesubstrate conveyor, while the second movable member is movable in adirection perpendicular to the conveying direction, or vice versa.

In a case where the first movable member is movable in the directionparallel to the conveying direction of the substrate conveyor and thesubstrate detector is held by the first movable member, the substratedetector is moved only in a direction parallel to the conveyingdirection. On the other hand, in a case where the substrate detector isheld by the second movable member, the substrate detector can be movedin both of the directions parallel to and intersecting with (e.g.perpendicular to) the conveying direction. In the latter case where thesecond movable member is moved only in a direction parallel to theconveying direction, it is practically the same as that the substratedetector is held by the first movable member. However, when the secondmovable member is moved in the direction intersecting the conveyingdirection also, operation and effects obtained are different from thosein the former case. For example, in the case where the circuit substratehas a cutout in its marginal portion on the downstream side in theconveying direction, the substrate detector can be moved to a locationdeviated from the cutout so that the presence of the cutout does notadversely influence the control of stopping the circuit substrate.Therefore, in the case where the substrate detector is moved in both ofthe directions parallel to and intersecting with the conveyingdirection, a freedom in detecting the circuit substrate is enhanced,particularly improving a freedom in the control of stopping the circuitsubstrate.

Whether the substrate detector is held by the first movable member or bythe second movable member, the substrate detector is automatically movedto the desired location at least in the direction parallel to theconveying direction, by the moving apparatus for moving the workinghead, and the location of the substrate detector is automaticallychanged. That is, the location of the substrate detector can be changedwithout bothering the operator and without the limitation in selectingthe position of the substrate supporting device, since the substratedetector is disposed on the side where a relevant operation for thecircuit substrate is performed. Hence, in the present mode of theworking system, the substrate detector is moved to the predeterminedlocation at which the substrate detector detects the predetermineddetection portion of the circuit substrate, and the circuit substrate isthen stopped at the desired position based on the result of thedetection, without causing the drawbacks as described above. Further,the inconvenience encountered in the case where the location of thesubstrate detector is fixed is solved. Still further, since the movingapparatus for the working head is utilized for moving the substratedetector, the object of the invention is economically attained.

A variety of effects can be obtained in the working system. Forinstance, in the case where the working system is theelectronic-circuit-component mounting system, effects such as enhancingthe efficiency in mounting electronic circuit components can be obtainedby the control of stopping the circuit substrate, as will be describedlater. On the other hand, in the case where the working system is theejection application system using the discharge nozzle, and the movingapparatus has an electric rotary motor as a drive source thereof and amotion transmitting mechanism including a feed screw and a nut and isconstructed such that a movable member is linearly moved, the stopposition is varied depending upon the dimensions and shape of thecircuit substrate such that the feed screw is fully utilized withrespect to its axial dimension, thereby enhancing the lifetime of themoving apparatus.

(2) The working system according to the mode (1), wherein the substratedetector includes a non-contact type detector which detects thepredetermined detection portion of the circuit substrate withoutcontacting the circuit substrate.

The non-contact type detector may be a photoelectric sensor as describedwith respect to the mode (3) below, or may be a proximity sensor.

The non-contact type detector can detect the predetermined detectionportion without contacting the circuit substrate, preventing wear of thesubstrate detector due to contact with the circuit substrate, therebyprolonging the lifetime of the substrate detector.

(3) The working system according to the mode (2), wherein thenon-contact type detector includes a reflection-type detector which hasa light emitting element and a light receiving element and detects thepredetermined detection portion of the circuit substrate such that alight emitted from the light emitting element and then reflected by thepredetermined detection portion is detected by the light receivingelement.

(4) The working system according to the mode (2) or (3), wherein thenon-contact type detector includes an imaging device for taking an imageof the predetermined detection portion of the circuit substrate.

The imaging device may consist of a surface imaging device whichcaptures a two-dimensional image of an object at a time, or may consistof a line sensor which has a multiplicity of imaging elements aligned ina straight row and iterates taking an image while being moved relativelyto the object.

(5) The working system according to the mode (4), wherein the imagingdevice also acts as a fiducial-mark imaging device for taking an imageof a fiducial mark on the surface of the circuit substrate to detect thestop position of the circuit substrate.

The fiducial mark may be a mark exclusively used for detecting the stopposition, or may be a part of the circuit substrate which is providedfor another purpose than detecting the stop position. For instance, inthe case where the circuit substrate is a printed wiring board, apredetermined part of a wiring pattern, e.g., a land, may be employed asthe fiducial mark.

According to the arrangement where an image of the fiducial mark istaken to detect the stop position of the circuit substrate, the stopposition is accurately obtained, thereby enhancing the accuracy of theoperation performed for the circuit substrate. Therefore, the movingapparatus is constructed such that the imaging device is moved with highaccuracy, so that the stop position of the circuit substrate can beexactly obtained. Consequently, the imaging device can also be moved toa predetermined location with high accuracy when the circuit substrateis detected, thereby improving accuracy of controlling the stop positionof the circuit substrate.

According to the above mode (5), a single imaging device can operate tocontrol the stop position of the circuit substrate, as well as to detectthe stop position, making the stop control economical.

(6) The working system according to the mode (5), wherein thepredetermined detection portion of the circuit substrate is the fiducialmark.

The fiducial mark used to detect the stop position is utilized forcontrolling the stop of the circuit substrate.

(7) The working system according to any one of the modes (1)-(6),wherein the substrate stop position controller includes a memory forstoring location-related information which relates to a location towhich one of the first movable member and the second movable memberwhich is movable at least in the direction parallel to the conveyingdirection is moved for detecting the predetermined detection portionwith the substrate detector.

The substrate detector is moved to the location (detection location) atwhich the substrate detector detects the predetermined detection portionso as to stop the circuit substrate at the desired stop position. Thedetection location varies depending upon the stop position of thecircuit substrate and a location of the predetermined detection portionon the surface of the circuit substrate (which will be simply referredto as the “setting of the detection portion” hereinafter). Therefore,the location-related information, which relates to the location to whichthe one of the first and second movable member is moved, is a piece ofinformation which enables the substrate detector to be stopped at thepredetermined detection location in accordance with the stop position ofthe circuit substrate and the setting of the detection portion.

The location-related information may be information representative ofthe location itself to which the one of the first and second movablemember should be moved so as to position the substrate detector at thedetection location for detecting the predetermined detection portion. Oralternatively, the location-related information may be variousinformation described below with respect to several modes.

(8) The working system according to the mode (7), wherein the memoryincludes a portion for storing, as the location-related information, apiece of information which varies depending upon at least one ofdimensions and a shape of the circuit substrate.

According to the above mode (8), the substrate detector can be moved toa location according to the at least one of the dimensions and shape ofthe circuit substrate, and consequently the circuit substrate can bestopped at a desired position according to the at least one of thedimensions and shape of the circuit substrate. For instance, in a casewhere the circuit substrate is to be stopped at the center of the rangeof movement of the working head in the conveying direction, the locationto which the substrate detector should be moved can be obtained when adimension of the circuit substrate in the conveying direction isavailable. It is noted, however, that in a case where the predetermineddetection portion is not the edge of the circuit substrate and adistance between the edge and the predetermined detection portion is notconstant, it is necessary for the location-related information toinclude the distance between the edge and the predetermined detectionportion.

(9) The working system according to the mode (7) or (8), wherein thememory includes a portion for storing, as the location-relatedinformation, a piece of information which varies depending upon adirection in which the circuit substrate is conveyed by the substrateconveyor.

For instance, in a case where the conveying direction of the circuitsubstrate by the substrate conveyor is switchable between a forwarddirection and a reverse direction, it is often preferable to change thestop position of the circuit substrate depending upon the conveyingdirection. In such a case, the location-related information should benaturally changed according to the conveying direction. Even in a casewhere the stop position of the circuit substrate is constantirrespective of the conveying direction, the location of thepredetermined detection portion on the circuit substrate in a directionparallel to the conveying direction in a state where the circuitsubstrate is stopped at the stop position may be varied in accordancewith the conveying direction, depending upon the setting of thedetection portion of the circuit substrate. Accordingly, thelocation-related information should be such a kind of information whichis varied depending upon the direction in which the circuit substrate isconveyed by the substrate conveyor.

(10) The working system according to any one of the modes (7)-(9),wherein the memory includes a portion for storing, as thelocation-related information, a piece of information for stopping thecircuit substrate at the center of the range of movement of the workinghead moved by the moving apparatus in the conveying direction.

The terms “stopping the circuit substrate at the center of the range ofmovement of the working head which is moved by the moving apparatus inthe conveying direction of the substrate conveyor” means that the centerof the circuit substrate in the direction of the conveyance of thecircuit substrate is made coincident with the center of the range ofmovement of the working head in the conveying direction. Hence, in acase where the predetermined detection portion is located at the centerof the circuit substrate in the direction parallel to the conveyingdirection, the substrate detector is to be located at the center of therange of movement of the working head in the conveying direction. On theother hand, in a case where the predetermined detection portion islocated at the edge of the circuit substrate on the downstream side inthe conveying direction or at a position adjacent to the edge, thesubstrate detector need be located at a position corresponding to thelocation of the predetermined detection portion in a state where thecircuit substrate is positioned at the center of the range of movementof the working head in the conveying direction. In this case, theposition of the substrate detector should be changed depending upon thedimension of the circuit substrate in the conveying direction. Hence,according to the above mode (10), the location-related information is apiece of information for locating the substrate detector at a constantposition (i.e. at the center of the range of movement of the workinghead in the conveying direction), or a piece of information for locatingthe substrate detector at a position which is varied depending upon thedimension of the circuit substrate in the conveying direction (e.g. theposition corresponding to the edge of the circuit substrate on thedownstream side in the conveying direction).

(11) The working system according to any one of the modes (7)-(10),wherein the memory includes a portion for storing kinds and stoppositions of a plurality of kinds of circuit substrates conveyed by thesubstrate conveyor, such that the stop positions are associated withrespectively corresponding kinds of the circuit substrates.

If kinds of two circuit substrates are different, the shapes anddimensions of the two substrates differ. According to the above mode(11), circuit substrates of different kinds can be stopped at anappropriate position depending upon their kinds.

(12) The working system according to any one of the modes (1)-(11),further including a component supplying device, wherein the working headincludes a component mounting head for mounting electronic circuitcomponents supplied from the component supplying device at a prescribedpoints on the circuit substrate which has been stopped at the stopposition.

The working head may have a single component mounting head, or aplurality of component mounting heads. In the latter case, the pluralityof component mounting heads may be arranged in a row in a directionparallel to the direction of movement of the second movable member.Alternatively, as described in JP-A-10-163677 for example, the pluralityof component mounting heads may be turned around a common axis ofturning by a component-mounting-head turning device disposed on thesecond movable member, and the component mounting heads may be stoppedat least at a component receiving/mounting position located on a path ofthe turning, at which the electronic circuit components are receivedfrom the component supplying device and mounted on the circuitsubstrate. As an alternative arrangement, receiving the electroniccircuit components and mounting the electronic circuit components may beperformed at respective stop positions. The component-mounting-headturning device may have a rotary body rotatable around an axis and arotary-body rotating device for rotating the rotary body at a givenangle in both of forward and reverse directions, and be constructed suchthat the plurality of component mounting heads are held and rotated bythe rotary body so that the component mounting heads are sequentiallystopped at stop positions including a component receiving position and acomponent mounting position. Alternatively, the component-mounting-headturning device may have an intermittent turning table which is a rotarybody capable of being intermittently turned around an axis, and anintermittent turning device for intermittently turning the intermittentturning table, and be constructed such that the plurality of thecomponent mounting heads are held by the intermittent turning table suchthat the component mounting heads are equiangularly spaced from eachother, so that the component mounting heads are sequentially stopped atthe respective stop positions including the component receiving positionand component mounting position. Further, the component-mounting-headturning device may be constructed such that the component-mounting-headturning device includes: a plurality of turning members which are ableto turn around a common axis of turning; and a turning motion applyingdevice including a cam mechanism for turning the respective turningmembers in accordance with a predetermined pattern of turning speed,such that each of the turning members is sequentially stopped at aplurality of predetermined stop positions at the timing differentiatedfrom those of the other turning members, and each of the turning membersholds a component mounting head such that the component mounting head isrotatable as well as axially movable and the component mounting headsare turned around the common turning axis.

(13) The working system according to the above mode (12), wherein thecomponent supplying device has a plurality of component feeders, each ofwhich has a component supply portion, contains a multiplicity ofelectronic circuit components of one kind, and is adapted tosequentially feed the electronic circuit components one by one to thecomponent supply portion, the plurality of component feeders beingarranged in a row extending in a direction parallel to the conveyingdirection of the substrate conveyor.

In an arrangement where the feature of the above mode (13) is combinedwith the feature of the mode (10), there is a high possibility that adistance of the movement of the component mounting head between thecomponent feeder and the circuit substrate can be reduced and therebyefficiency in mounting the components is enhanced. More specifically, bylocating the component supplying device, as well as stopping the circuitsubstrate, at the center of the range of movement of the componentmounting head, which is moved by the moving apparatus, in the conveyingdirection of the substrate conveyor, the centers of the componentsupplying device and the circuit substrate coincide with each other.Therefore, a probability that a total distance of movement of thecomponent mounting head required for mounting all electronic circuitcomponents on the circuit substrate is made smaller than the case wherethe centers of the circuit substrate and the component supplying devicein the conveying direction do not coincide with each other, is high, aslong as a probability that a location at which the electronic circuitcomponent (fed from the component supply portion of each componentfeeder of the component supplying device) is to be mounted is designatedto a specific point on the circuit substrate, is uniform all over amounting surface of the circuit substrate.

Further, in a case where an image of the electronic circuit component iscaptured by the image taking device when the electronic circuitcomponent is taken out from the component feeder, to detect aholding-position error and correct the holding-position error before thecomponent is mounted on the circuit substrate, when the image takingdevice is located between the component supplying device and thesubstrate conveyor and at the center of the row of the componentfeeders, a probability that a total distance of movement of thecomponent mounting head is reduced is high. The component mounting headis necessarily moved to a position to be opposed to the image takingdevice after receiving the electronic circuit component, so that theimage taking device takes the image of the electronic circuit component.The component mounting head is then moved to a position corresponding toa mounting point on the circuit substrate where the electronic circuitcomponent is to be mounted. Therefore, stopping the circuit substrate atthe center in the conveying direction makes an entirety of the circuitsubstrate located in the vicinity of the image taking device, therebyenhancing the probability that the total distance of movement of thecomponent mounting head is reduced.

Similarly to that of the mode (10), the feature of each of the modes(8), (9), (11), etc. may be employed to have the centers of the circuitsubstrate and the component supplying device in the conveying directioncoincident. In such a case, a combination of the feature of the abovemode (13) with the feature of one of the modes (8), (9), (11), etc. canproduce the same effects as produced by the combination of features ofthe modes (10) and (13).

However, a combination of the features of the modes (8) and (13) cangive an effect unique to the combination, too. For instance, when thecircuit substrate has a cutout at its edge on the downstream side in theconveying direction, the location of the substrate detector (orlocations of the first and second movable members) is predetermined suchthat a portion of the downstream-side edge of the circuit substratewhere the cutout is not formed is detected as the predetermineddetection portion by the substrate detector, and thereby the circuitsubstrate with the cutout can be stopped at the same relative locationwith respect to the component supplying device as that of the circuitsubstrate without the cutout. Further, in a case where (i) a size of thecircuit substrate, (ii) the number of kinds of the electronic circuitcomponents to be mounted, and (iii) the number of lots of the involvedcircuit substrates, are all small, the stop positions of the respectivetypes kinds of the circuit substrates may be differentiated and a groupof component feeders for supplying electronic circuit components to aparticular kind of the circuit substrate is beforehand disposed at alocation corresponding to the stop position of the relevant type of thecircuit substrate. According to this arrangement, groups of componentfeeders need not be replaced, but only the stop position of the circuitsubstrates is changed, thereby enhancing efficiency of the mountingoperation for a plurality of types of circuit substrates where the typeof the circuit substrate is frequently changed.

By combining the features of the modes (11) and (13), multiple componentfeeders mounted on a single component supplying device can be used formounting electronic circuit components on a plurality of types ofcircuit substrates. In the case where the number of kinds of theelectronic circuit components to be mounted on the plurality of types ofcircuit substrates is smaller than the number of component feedersdisposed on the component supplying device, component feeders formounting electronic circuit components on different types of circuitsubstrates can be concurrently disposed on the single componentsupplying device. More specifically described, groups of exclusivefeeders, each of which groups supplies electronic circuit components onone type of circuit substrate exclusively, are disposed on the componentsupplying device, with a group of feeders which supplies commonelectronic circuit components on a plurality of types of circuitsubstrates is disposed between two groups of the exclusive feeders. Theplurality of types of circuit substrates are stopped at the positionscorresponding to the respective groups of the exclusive feeders, therebyenabling efficient mounting of electronic circuit components on theplurality of types of circuit substrates when the type of the circuitsubstrates is frequently changed.

(14) A working system for a circuit substrate, comprising:

-   -   a substrate conveyor which conveys a circuit substrate along a        straight line in a conveying direction, and is capable of        stopping the circuit substrate at a desired position in the        conveying direction;    -   a moving apparatus having a first movable member which is        movable in one of a first direction and a second direction which        intersect with each other in a plane parallel to a surface of        the circuit substrate which has been conveyed by the substrate        conveyor and then stopped, and a second movable member which is        held by the first movable member such that the second movable        member is movable in the other of the first direction and the        second direction, the moving apparatus moving the second movable        member to a desired location in the plane;    -   a stopper which is held by one of the first movable member and        the second movable member which one is movable in at least a        direction parallel to the conveying direction to a location in a        path of conveyance of the circuit substrate by the substrate        conveyor so as to be brought into contact with the circuit        substrate to stop the circuit substrate;    -   a stopper moving device which operates to move the stopper to an        operative position in the path of conveyance of the circuit        substrate and to an inoperative position away from the path of        conveyance; and    -   a working head which is held by the second movable member and        performs a plurality of operations for prescribed points on the        circuit substrate which has been stopped by the stopper.

The feature of each of the modes (7)-(13) is applicable to the workingsystem for a circuit substrate according to the present mode (14). Inthis regard, however, the term “for detecting the predetermineddetection portion” is replaced with the term “for stopping the circuitsubstrate by the stopper”.

The stopper functions to stop the circuit substrate by being broughtinto contact with the circuit substrate. The stopper is automaticallymoved, by the moving apparatus disposed on the side where the operationfor the circuit substrate is performed, to the desired location at leastin the direction parallel to the conveying direction. Therefore,similarly to the case where the substrate detector detects thepredetermined detection portion of the circuit substrate to control thestop position of the circuit substrate, the stopper can be moved to thepredetermined location where the circuit substrate is to be stopped,without causing any inconvenience, and thereby giving various effects tothe working system.

(15) The working system according to the mode (14), comprising:

-   -   an arrival detector which is held by one of the first movable        member and the second movable member which is movable at least        in the direction parallel to the conveying direction, and which        detects that the circuit substrate has reached a position where        the circuit substrate is brought into contact with the stopper;        and    -   a conveyor controller which stops the substrate conveyor in        response to the detection by the arrival detector that the        circuit substrate has reached the position where the circuit        substrate is brought into contact with the stopper.

The arrival detector may be of contact type such as a limit switch, ormay be of non-contact type such as a photoelectric sensor or proximityswitch. In a case where a photoelectric sensor is employed, thephotoelectric sensor may be of reflection type or transmission type.

It may be arranged such that the circuit substrate is decelerated beforebeing brought into contact with the stopper. For instance, in additionto the arrival detector, an approach detector may be employed to detectthe circuit substrate coming close to the stopper so that the circuitsubstrate is decelerated upon detection of the circuit substrateapproaching the stopper. Thus decelerating the circuit substrate lowersthe undesirable impact of the circuit substrate being brought intocontact with the stopper. For instance, in the case where electroniccircuit components have been mounted on the circuit substrate but notfixed to the circuit substrate yet, displacement of the electroniccircuit components from respective nominal positions caused upon thecircuit substrate is stopped, is avoided. The above mode (15) can beconsidered to be one example of the case where both the substratedetector and the stopper are employed by the working system describedwith respect to the mode (21) below. In this case, at least one of thearrival detector and the substrate detector corresponds to the substratedetector in the working system as described in the mode (21).

(16) The working system according to any one of the modes (1)-(15),

-   -   wherein the substrate conveyor is a belt conveyor including at        least one pair of pulleys, a belt entrained around the at least        one pair of pulleys, and a drive assembly which rotates at least        one of the at least one pair of pulleys.

(17) The working system according to the mode (16), wherein the beltconveyor includes: a pair of belts which are spaced from each other in adirection perpendicular to the conveying direction; and a pair ofsubstrate guides for the pair of belts, respectively, the substrateguides being disposed parallel to respective corresponding belts tofunction to guide opposite side faces of the circuit substrate.

(18) The working system according to the mode (17), wherein the beltconveyor includes an interval changing device for changing an intervalbetween the pairs of belts and substrate guides.

The interval changing device may be adapted such that the intervalbetween the pairs of belts and substrate guides is manually changed bythe operator, or may be alternatively provided with a drive source toautomatically change the interval. The drive source may consist of anelectric rotary motor. The automatically changing the interval may beimplemented in a way similar to one as described in unpublished JapanesePatent Applications Nos. 2000-374934 and 2001-301549, both by thepresent applicant.

(19) The working system according to any one of the modes (1)-(18),wherein the first movable member is movable in the direction parallel tothe conveying direction of the substrate conveyor, while the secondmovable member is movable in the direction perpendicular to theconveying direction.

(20) The working system according to any one of the modes (1)-(18),wherein the first movable member is movable in the directionperpendicular to the conveying direction of the substrate conveyor,while the second movable member is movable in the direction parallel tothe conveying direction.

(21) A working system for a circuit substrate, comprising:

-   -   a substrate conveyor which conveys a circuit substrate along a        straight line in a conveying direction, and is capable of        stopping the circuit substrate at a desired position in the        conveying direction;    -   a moving apparatus having a movable member which is movable at        least in a direction parallel to the conveying direction of the        substrate conveyor, and moves the movable member to the desired        location in the conveying direction;    -   a working head which is held by the movable member and performs        a plurality of operations for prescribed points on the circuit        substrate which has been stopped;    -   at least one of (a) a substrate detector which is moved by the        moving apparatus at least in a direction parallel to the        conveying direction, and detects a detection portion of the        circuit substrate, which detection portion is predetermined as        an object to be detected by the substrate detector, while the        circuit substrate is conveyed by the substrate conveyor, and (b)        a stopper which is moved by the moving apparatus in at least a        direction parallel to the conveying direction to a location in a        path of conveyance of the circuit substrate by the substrate        conveyor, so as to be brought into contact with the circuit        substrate to stop the circuit substrate;    -   a substrate stop position controller which controls the moving        apparatus to have the at least one of the substrate detector and        the stopper move to a predetermined location, and controls at        least one of the substrate conveyor and the stopper such that        the substrate conveyor is controlled based on a result of a        detection of the detection portion by the substrate detector        positioned at the predetermined location and the stopper is        controlled to be brought into contact with the circuit        substrate, so as to control a stop position at which the circuit        substrate is stopped.

For example, in the case where the working system is a screen printingsystem where a solder cream or others is printed on the circuitsubstrate through a screen mask, when a squeegee device as the workinghead is made movable along a straight line direction of which iscoincident with the conveying direction, the above-indicated movablemember can be employed as the member which holds and moves the squeegeedevice. Further, in the case where the substrate supporting device forsupporting the circuit substrate is movable to a desired position in adirection intersecting (preferably perpendicular to) the conveyingdirection of the substrate conveyor in a plane parallel to the surfaceof the circuit substrate which is supported by the substrate supportingdevice, the working head as held by the movable member and the circuitsubstrate as supported by the substrate supporting device can be movedrelatively to each other in the plane parallel to the surface of thecircuit substrate. A working system including the moving apparatusadapted to move the movable member to a desired position in the planeparallel to the surface of the circuit substrate as supported by thesubstrate supporting device corresponds to the working system asdescribed with respect to the mode (1) or (14), for example.

Each of the features described with respect to the modes (2)-(13),(15)-(20) is applicable to the working system according to the abovemode (21).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view showing an electronic-circuit-componentmounting system as a first embodiment of the invention.

FIG. 2 is a side elevational view of the electronic-circuit-componentmounting system.

FIG. 3 is a top plan view showing a PWB conveyor of theelectronic-circuit-component mounting system.

FIG. 4 is a side elevational view of the PWB conveyor.

FIG. 5 is a front elevational view showing a stationary guide of the PWBconveyor.

FIG. 6 is a front elevational view (partly in cross section) of theelectronic-circuit-component mounting system.

FIG. 7 is a side elevational view showing a component mounting device ofthe electronic-circuit-component mounting system.

FIG. 8 is a front elevational view showing a PWB detector of theelectronic-circuit-component mounting system.

FIG. 9 is a block diagram showing part of a controller which controlsthe electronic-circuit-component mounting system, which part is mostrelevant to this invention.

FIG. 10 is a block diagram indicating construction of a RAM of acomputer principally constituting the controller.

FIG. 11 is a view illustrating a stop control in conveying a PWB by thePWB conveyor.

FIG. 12 is a view illustrating another stop control in conveying the PWBby the PWB conveyor.

FIG. 13 is a view illustrating still another stop control in conveyingthe PWB by the PWB conveyor.

FIG. 14 is a view illustrating a stop control in conveying PWBs by thePWB conveyor, in a case where the electronic-circuit-component mountingsystem is operated to mount electronic circuit components on two kindsof PWBs.

FIG. 15 is a top plan view showing an electronic-circuit-componentmounting system as a second embodiment of the invention.

FIG. 16 is a top plan view showing an electronic-circuit-componentmounting system as a third embodiment of the invention.

FIG. 17 is a view for explaining how a fiducial-mark camera takes animage of, and detects, a downstream-side edge of the PWB, in theelectronic-circuit-component mounting system of FIG. 16.

FIG. 18 is a view for explaining how a fiducial-mark camera takes animage of, and detects, a fiducial mark of the PWB, in theelectronic-circuit-component mounting system of FIG. 16.

FIG. 19 is a side elevational view showing parts including a stopper ofan electronic-circuit-component mounting system as a fourth embodimentof the invention.

FIG. 20 is a top plan view showing an adhesive coating system as a fifthembodiment of the invention.

FIG. 21 is a front elevational view (partly in cross section) of theadhesive coating system.

FIG. 22 is a top plan view schematically showing anelectronic-circuit-component mounting system as a sixth embodiment ofthe invention.

BEST MODE FOR CARRYING OUT THE INVENTION

There will be described in detail by way of example anelectronic-circuit-component mounting system to which the invention isapplied, by reference to the accompanying drawings.

In FIG. 1, a reference sign 10 denotes a base as a main body of theelectronic-circuit-component mounting system 11. On the base 10 isdisposed: a wiring-board conveyor (PWB conveyor) 14 as a substrateconveyor for conveying a printed-wiring board (PWB) 12 as a kind of acircuit substrate in an X-axis direction (horizontal direction as seenin FIG. 1); a PWB supporting device 15 as a substrate supporting devicewhich supports the PWB 12; a component mounting device 18 for mountingelectronic circuit components 16 (shown in FIG. 6) on the PWB 12; and acomponent supplying device 20 for supplying the electronic circuitcomponents 16 to the component mounting device 18.

Over the entirety of the electronic-circuit-component mounting system 11is set a horizontal X-Y coordinate plane, and movements of variousmovable components or members of the system 11 are predetermined on theX-Y coordinate plane. As shown in FIGS. 1 and 2, the component supplyingdevice 20 is disposed adjacent to the PWB conveyor in a Y-direction,such that the component supplying device 20 is stationary and itslocation is fixed.

The component supplying device 20 has a component supplying table 34where multiple component feeders 30 (which will be simply referred to as“feeder(s) 30”) are arranged on a feeder support table 32. Each of themultiple feeders 30 contains a multiplicity of electronic circuitcomponents 16 of a same kind, and the components 16 are sequentially fedto a predetermined component supply portion one by one. These feeders 30are disposed on the feeder support table 32 such that the componentsupply portions of the feeders 30 are aligned along a straight lineparallel to an X-axis.

In this first embodiment, the electronic circuit components 16 suppliedby the feeders 30 take the form of an electronic-circuit-componentcarrier tape accommodating a multiplicity of electronic circuitcomponents arranged in a lengthwise direction of the tape at apredetermined pitch. The electronic-circuit-component carrier tape isaccommodated in a tape accommodating device and fed by a tape feeder tofeed the electronic circuit components 16 to the component supplyportion. It is noted that the feeder may not be a tape feeder, but maybe a bulk feeder which stores in bulk a number of electronic circuitcomponents in a component-store device thereof, arranges the electroniccircuit components into a single array, and supplies the electroniccircuit components one by one from the component supply portion thereofby operation of a feeding device which uses vibration, an incline,airflow, conveyor belt or others, or a combination of some of these tofeed the electronic circuit components.

There will be described the PWB conveyor 14.

The PWB conveyor 14 has PWB guides 110, 112 as a pair of substrateguides, as shown in FIG. 3. The PWB guides 110, 112 are disposedhorizontally and in parallel to the X-axis. The PWB guide 110 isdisposed on the base 10 such that a location of the PWB guide 110 isfixed, while the PWB guide 112 is disposed such that the PWB guide 112is movable in a Y-axis direction to approach and get away from the PWBguide 110. The PWB guides 110 and 112 are spaced from each other in theY-axis direction perpendicular to the X-axis direction. Hereinafter, thePWB guide 110 is referred to as a stationary guide 110, while the PWBguide 112 is referred to as a movable guide 112.

On each of a surface of the stationary guide 110 and a surface of themovable guide 112, which surfaces are opposed to each other, there isrotatably attached a pair of groove-type pulleys 120 as rotary membersat the opposite longitudinal end portions of each surface, as shown inFIG. 3. Between each pair of the pulleys 120 of the stationary andmovable guides 110, 112, a belt guide 122 as a longitudinal guidingmember is fixed, as shown in FIG. 5 in which is shown the stationaryguide 110 as a representative example. An endless belt 124 as anentrained member having no end is wound around each group consisting ofone pair of the groove-type pulleys and the belt guide 122, such thattraveling of the endless belts 124 is guided by the respective groups.On an inner circular surface of the endless belt 124, there is provideda protruding line at the center of the width thereof. The protrudingline is fitted in a groove of each groove-type pulley 120 such thatlongitudinal movement, relative to the pulleys 120, of the endless belt124 is permitted and that the endless belt 124 is properly positioned inthe direction of its width with respect to the pulleys 120. Although itis not shown in drawings, an upper surface of the belt guide 122 has agroove formed similarly to the groove-type pulleys 120, to position theendless belt 124 in the direction of its width.

Further, the endless belt 124 on the side of the stationary guide 110 isentrained around: a plurality of tension pulleys 128 as members forapplying a tensile force to the endless belt 124 and which is rotatablyattached to the stationary guide 110; a plurality of groove-type pulleys130; and a driven pulley 132 as a rotary driven member, as shown in FIG.5. The driven pulley 132 is, as shown in FIGS. 3 and 4, fixed to aspline shaft 138 as a rotation transmitting shaft which is rotatablysupported at its both ends by the stationary guide 110 and a supportmember 136, respectively. In the first embodiment, as shown in FIG. 3,the support member 136 is a longitudinal member which is provided on theouter side of the movable guide 112, that is, on the side remote fromthe stationary guide 110, such that the support member 136 is parallelto the movable guide 112 and the location of the support member 136 isfixed. A first sprocket 140 is fixed to the spline shaft 138, which islinked to a second sprocket 146 through a chain 148 as an entrainedmember. The second sprocket 146 is a rotary member fixed to an outputshaft 144 of a PWB conveyor motor 142 as a drive source in the form ofan electric motor. In the first embodiment, the PWB conveyor motor 142is an electric motor which is controlled with respect to its rotationalvelocity, but is not controlled with respect to its rotational position.

As shown in FIG. 4, the endless belt 124 on the side of the movablemember 112 is entrained around a plurality of tension pulleys 156 asmembers for applying a tensile force to the endless belt 124 and aplurality of groove-type pulleys 158 (only one tension pulley 156 andone groove-type pulley are shown in FIG. 4), both kinds of pulleys beingrotatably fixed to the movable guide 112, and is also entrained around adriven pulley 160 as a rotary driven member. The driven pulley 160 isrotatably, and axially immovably, fixed to the movable guide 112, andsplined to the spline shaft 138. That is, the driven pulley 160 issplined to the spline shaft 138 such that the driven pulley 160 isaxially movable, but not rotatable, relatively to the spline shaft 138.Hence, when the PWB conveyor motor 142 is activated, the sprockets 140,146 are rotated, the spline shaft 138 is rotated, and the driven pulleys132, 160 are also rotated, so that the pair of endless belts 124 arecirculated in synchronization with each other.

The PWB 12 is placed such that its opposite edge portions are set onstraight portions of the pair of endless belts 124, and conveyed inaccordance with circulation of the endless belts 124 by friction forcegenerated between the PWB 12 and the endless belts 124. Each of theendless belts 124 provided on the horizontally disposed stationary andmovable guides 110, 112, supports the PWB 12 in a horizontal attitude.The PWB 12 is conveyed in the X-axis direction along extension of thestationary and movable guides 110, 112, that is, the PWB 12 is conveyedin a conveying direction along a straight line. The energization andde-energization of the PWB conveyance motor 142 is controlled by acontroller as described below, so that the PWB 12 is stopped at apredetermined stop position in the conveying direction. The PWBconveyance motor 142 is rotatable in both of forward and reversedirections, and accordingly the PWB conveyor 14 can convey the PWB 12 inboth of forward and reverse directions. In the first embodiment, a PWBconveyance motor 142, chain 148, sprockets 140, 146, spline shaft 138and other members constitute a rotary drive assembly 162 for driving thedriven pulleys 132, 160 etc., which drive assembly 162 cooperates withthe groove-type pulleys 120, 130, 158, driven pulleys 132, 160, conveyorbelt 124 entrained around the pulleys 120 and other pulleys, stationaryguide 110, movable guide 112 and the endless belts 124 to constitute thePWB conveyor 14. That is, the PWB conveyor 14 is a belt conveyor.

On the stationary and movable guides 110, 112, there is respectivelyfixed a guide member 170 as shown in FIGS. 3-5. The thus fixed guidemember 170 constitutes guiding means and serves as a guiding portion ofthe stationary and movable guide 110, 112. The guide member 170 has aplanar shape of a substantially same length as the stationary andmovable members 110, 112, and has a vertical guide surface 172. The pairof the guide surfaces 172 respectively guide side surfaces 173 of thePWB 12 opposite to each other in the direction of the width thereof, toguide traveling of the PWB 12 in the longitudinal direction of thestationary and movable guides 110, 112. Thus, the stationary and movableguides 110, 112 are spaced in the Y-axis direction which is a directionperpendicular to the direction in which the PWB 12 is conveyed, and isparallel to the pair of endless belts 124, so as to guide the PWB 12 bythe guide surfaces 172.

The above-described two guide members 170 have respective pressingportions 174 as members formed integrally with the guide members 170along the longitudinal direction of the guide members 170. The pressingportion 174 functions to prevent levitation of the PWB 12 during theconveyance thereof, as well as to clamp the PWB 12 while electroniccircuit components are mounted.

The PWB supporting device 15 is disposed below the plane on which thePWB 12 is conveyed by the PWB conveyor 14 and adjacent to the componentsupplying device 20 in the Y-axis direction. The PWB supporting device15 (not shown) includes a supporting table and a plurality of supportingmembers disposed on the supporting table, and can be lifted and lowered,similarly to a wiring-board supporting device as described inJP-A-11-195899, for example. When the supporting table is elevated by alifting/lowering device, the supporting table is brought into contactwith a back surface of the PWB 12 so as to lift the PWB 12 away from thepair of endless belts 124 to press the PWB 12 onto the pressing portions174 of the guide members 170 as well as to support the PWB 12 from theunder side, in a state where an upper surface 180 of the PWB 12, whichis a mounting surface as a kind of working surface on which theelectronic circuit components 16 are mounted, assumes a horizontalattitude. A pair of clamp members disposed on the supporting tableclamps the opposite edge portions of the PWB 12 which portions areparallel to the conveying direction of the PWB 12, between the clampmembers and the pair of pressing portions 174. The clamp members and thepressing portions 174 constitute a PWB clamp device, which cooperateswith the PWB supporting device 15 to constitute a PWB holding device.

The stationary guide 110 and the supporting member 136 respectivelysupport opposite ends of a plurality of guide rods 190 as guidingmembers such that the guide rods 190 are fixed in position, as shown inFIG. 3, and also rotatably support opposite ends of each of a pluralityof feed screws 192. The guide rods 190 and feed screws 192 are disposedparallel to the Y-axis direction. The feed screws 192 are respectivelyscrewed into rail nuts 196 fixed to the movable guide 112, while guideblocks 200 as guided members are axially slidably fitted on the guiderods 190. A third sprocket 202 as a rotary member is attached to an endportion of each of the feed screws 192 which end portion extendsoutwardly from the stationary guide 110, i.e., in the direction awayfrom the movable guide 112, such that each third sprocket 202 is notable to rotate relatively to the feed screw 192.

A plurality of tension sprockets 206 are rotatably disposed on the outerside of the stationary guide 110, such that the sprockets 206 arerotatable around respective rotation axes parallel to a rotation axis ofthe third sprocket 202. A chain 208 as an entrained member having no endis wound around these sprockets 202, 206. A hand wheel 218 as anoperating member is engaged with one of the two feed screws 192, asindicated by a chain double-dashed line in FIG. 3, so that when theoperator turns the hand wheel 218, the feed screws 192 are rotated tomove the movable member 112 in the Y-axis direction, and width of thePWB conveyor 14 is changed.

The rotary motion of the one feed screw 192 is transmitted to the otherfeed screw 192 via the third sprocket 202 and the chain 208. Thus, thetwo feed screws 192 are rotated in synchronization so that the movablemember 112 approach, and is moved away from, the stationary guide 110,uniformly in its longitudinal direction, making it possible to changethe width of the PWB conveyor 14. In the first embodiment, the thirdsprocket 202, chain 208 and others constitute a rotary motiontransmitting mechanism, which cooperates with the feed screws 192, railnuts 196 and others to constitute an interval changing device 214.

There will be described the component mounting device 18.

As shown in FIGS. 6 and 7, the component mounting device 18 is adaptedsuch that a component mounting head 230 as a component holding headwhich is a kind of working head is moved to a desired location in theX-Y coordinate plane defined by the X-axis and Y-axis which areperpendicular to each other, and the electronic circuit components 16supplied from the component supplying device 20 are mounted on theprescribed points on the upper surface 180 of the PWB 12 which has beenstopped.

Therefore, as shown in FIG. 1, on each of the opposite sides of the PWBconveyor 14 (disposed on the base 10) in the Y-axis direction isdisposed a ball screw 234 extending in a direction parallel to theX-axis direction, and screwed into a nut 238 (only one of which is shownin FIG. 6) disposed on an X-axis slide 236. Each of these ball screws234 is rotated by an X-axis slide moving motor 240 (shown in FIG. 1), sothat the X-axis slide 236 is moved to a desired location in the X-axisdirection. The movement of the X-axis slide 236 is guided by an X-axisguiding device including guide rails 242 (shown in FIG. 6) as guidingmembers which are provided under the two ball screws 234, respectively,and guide blocks 244 as guided members disposed on the X-axis slide 236.The X-axis slide 236 as described above constitutes a first movablemember, while the nuts 238, ball screws 234, X-axis slide moving motor240 and others constitute an X-axis slide moving device 246.

A ball screw 250 (shown in FIG. 6) is disposed on the X-axis slide 236,in parallel to the Y-axis direction, and a Y-axis slide 252 is attachedto the X-axis slide 236 by screwing together the ball screw 250 and anut 254. The ball screw 250 is rotated by a Y-axis slide moving motor256 (shown in FIG. 1) via gears 258, 260, and the Y-axis slide 252 isthereby moved to a desired location in the Y-axis direction with beingguided by a Y-axis guiding device including a pair of guide rails 262 asguiding members. Thus, the Y-axis slide 252 described above constitutesa second movable member, while the nut 254, ball screw 250, Y-axis slidemoving motor 256 and others constitute a Y-axis slide moving device 264.

The Y-axis slide 252 holds the component mounting head 230, a headlifting/lowering device 270 and a head rotating device 272, as shown inFIGS. 6 and 7, and the component mounting head 230 with the othermembers constitute a component mounting unit 274. In the firstembodiment, the X-axis slide 232, Y-axis slide 252, X-axis slide movingdevice 246 and Y-axis slide moving device 264 constitute an XY robot 266as a moving apparatus, which moves the component mounting head 230 to adesired location in the horizontal X-Y coordinate plane. It is notedthat the component mounting unit 274 may consist of a plurality of suchcomponent mounting units.

A range within which the component mounting head 230 is moved by the XYrobot 266 is determined to be an adequate scope for receiving anelectronic circuit components 16 from all of the feeders 30 of thecomponent supplying device 20, as well as for mounting electroniccircuit components 16 on the PWB 12 of a largest size. The PWBsupporting device 15 and the component supplying device 20 are disposedat the center of the range of movement of the component mounting head230 in the conveying direction of the PWB conveyor 14. Morespecifically, the center of the PWB supporting device 15 in theconveying direction of the PWB conveyor 14 is coincident with the centerof the range of movement of the component mounting head 230 in theconveying direction. As to the component supplying device 20, one of thecomponent supply portions of the multiple feeders 30 arranged in the rowin the X-axis direction, which one is positioned at the center in theX-axis direction, is located at the center of the range of movement ofthe component mounting head 230 in the conveying direction.

The head lifting/lowering device 270 is an advancing/retracting devicewhich has a head lifting/lowering motor 276 as a drive source, as shownin FIG. 6, and lifts and lowers the component mounting head 230, so thatthe component mounting head 230 is moved toward and away from the PWB12. The head rotating device 272 has a head rotating motor 278 as adrive source, and rotates the component mounting head 230 around itsaxis. These head lifting/lowering device 270 and head rotating device272 are constructed similarly to a head lifting/lowering device (ornozzle-holder elevating and lowering device) and head rotating device(or nozzle-holder rotating device), respectively, which are described inunpublished Japanese Patent Application No. 2001-287339 by the presentapplicant, and therefore detailed description thereof is omitted.

The component mounting head 230 has a holder 280, and holds a suctionnozzle 282 as a component holding member. An electronic circuitcomponent 16 is suctioned by negative pressure by the suction nozzle282, and mounted on the PWB 12. The suction nozzle 282 has a main body284 and a suction tube 286. The suction nozzle 282 is in communicationwith a negative pressure source, a positive pressure source, and theatmosphere, respectively via an air passage or other parts including arotary valve, a hose, and a solenoid-operated direction-switch valvethat are not shown. By switching the solenoid-operated direction-switchvalve, the suction tube 286 is alternately brought into communicationwith the negative pressure source, positive pressure source andatmosphere, so as to hold and/or release the electronic circuitcomponent 16.

The Y-axis slide 252 has a fiducial-mark imaging system 292 for takingan image of a fiducial mark 290 (shown in FIG. 1) on the PWB 12, and ismoved by the XY robot 266 to the desired location in the horizontalplane, as shown in FIG. 7. The fiducial-mark imaging system 292 has afiducial-mark camera 294 as an imaging device and a first lightingdevice 296. In the first embodiment, the fiducial-mark camera 294 has aCCD (charge-coupled device) as a kind of solid-state imaging detectorand a lens system including an image forming lens, and takes the form ofa CCD camera as a surface imaging device which is a kind of imagingdevice capable of taking a two-dimensional image of an object at once.The fiducial-mark camera 294 is disposed on the Y-axis slide 252, suchthat the fiducial-mark camera 294 is supported by a holding member (notshown) such that a center axis of the fiducial-mark camera 294 isvertical and the fiducial-mark camera 294 is oriented downward. The CCDis such that a multiplicity of minute light receiving elements arearranged on a plane, and generates electric signals depending uponrespective states of light reception at the respective light receivingelements. That is, the multiplicity of light receiving elements forms animaging area or imaging screen.

As shown in FIGS. 7 and 8, the Y-axis slide 252 holds a PWB detector 308as a substrate detector. The PWB detector 308 includes a firstphotoelectric sensor 310 and a second photoelectric sensor 312, and ismoved to a desired position in a horizontal plane or the X-Y coordinateplane by the XY robot 266. These photoelectric sensors 310, 312 are anon-contact type detector as a kind of PWB detector as a substratedetector which detects an object without contacting the object, and aredisposed such that these sensors 310, 312 are spaced from each other inthe conveying direction.

In the first embodiment, each of the photoelectric sensors 310, 312 isof reflective type, and has a light emitting element 314 and a lightreceiving element 316. A light radiated from the light emitting element314 is reflected by the object and then received or detected by thelight receiving element 316, to thereby detect the object. Each of thephotoelectric sensors 310, 312 in the first embodiment is adapted tooutput an OFF signal in a case where the light receiving element 316does not receive a reflected light, and output an ON signal in a casewhere the light receiving element 316 receives a reflected light in anamount beyond a threshold value.

As shown in FIG. 1, a component imaging system 330 is immovably fixed tothe X-axis slide 236 at a position corresponding to one of the two ballscrews 234 for moving the X-axis slide 236 and between the componentsupplying device 20 and the PWB conveyor 14. The construction of thecomponent imaging system 330 has little relation to the invention and istherefore only briefly described.

The component imaging system 330 has an imaging device 332 and a secondlighting device 334, as shown in FIG. 6. In the first embodiment, theimaging device 332 has a component camera 336 for taking an image of anelectronic circuit component 16 and a light guiding device 338 whichguides an image forming light for forming the image of the electroniccircuit component, into the component camera 336. In the firstembodiment, the component camera 336 is a surface imaging device in theform of a CCD camera, similar to the fiducial-mark camera 294 asdescribed above. Once the component mounting head 230 is moved by the XYrobot 266 to a position corresponding to the ball screw 234 in theY-axis direction and above the light guiding device 338, the componentcamera 336 can take an image of the electronic circuit component 16. Inthe first embodiment, the component imaging system 330 is constructedsuch that the component camera 336 can take an image of a frontelevational image and a projective image of the object.

The electronic-circuit-component mounting system 11 is controlled by acontroller 350 shown in FIG. 9, in which only a portion of the system 11relevant to the invention is shown. The controller 350 is mainlyconstituted by a computer 352 in which a PU (Processing Unit) 354, ROM356, RAM 358 and input/output port 360 are connected to one another viaa bus line 362. To the input/output port 360 are connected variousdevices such as computers and detectors, e.g., an image processingcomputer 366 for analyzing image data captured by the fiducial-markcamera 294 and the component camera 336, the photoelectric sensors 310,312 and encoders 368, 370. In the fiducial-mark imaging system 292 andthe component imaging system 300, imaging and lighting operations areimplemented under control of the controller 350.

Further, various actuators such as the X-axis slide moving motor 240 isconnected to the input/output port 360 via a driver circuit 380. TheX-axis slide moving motor 240 with other members constitute a drivesource. In the first embodiment, each of the X-axis slide moving motor240, Y-axis slide moving motor 256, head lifting/lowering motor 276 andhead rotating motor 278 consists of an electric rotary motor, serving asa servomotor which is controllable with high accuracy with respect toits rotation angle. However, each of these motors may be a steppingmotor. The rotation angle of each of the various motors including theX-axis slide moving motor 240 is detected by an encoder, and the eachmotor is controlled on the basis of the outputs of the encoder. FIG. 9shows, by way of example, encoders 368, 370 provided to the X-axis slidemoving motor 240 and Y-axis slide moving motor 256, respectively.

The RAM 358 includes a program memory, PWB detection location datamemory etc., as well as a working memory, as shown in FIG. 10, forstoring various programs and data. The program memory stores variousprograms, data etc. such as a main routine (not shown) and a componentmounting program used for mounting the electronic circuit components 16on the PWB 12. These programs and data may be read from an externalmemory device, or may be supplied from a host computer controlling aplurality of working systems for performing operations on circuitsubstrates, each of the systems including the presentelectronic-circuit-component mounting system 11.

In the first embodiment, when the PWB 12 is conveyed by the PWB conveyor14, the PWB 12 is stopped when the edge of the PWB 12 on the downstreamside in the conveying direction is detected by the first and secondphotoelectric sensors 310, 312. That is, in the first embodiment, theedge of the PWB 12 on the downstream side in the conveying directionconstitutes a predetermined detection portion, and the PWB detectionlocation data memory stores data representative of positions to whichthe X-axis and Y-axis slides 236, 252 should be moved to detect thepredetermined detection portion of the PWB 12 by the PWB detector 308.

The first and second photoelectric sensors 310, 312 are moved by the XYrobot 266 to respective desired locations in the plane of movement ofthe component mounting head 230. By appropriately predetermining theselocations, the PWB 12 as conveyed by the PWB conveyor 14 can be stoppedat a desired position in the path of the conveyance. In the firstembodiment, any one of a plurality of kinds of PWB 12 having respectiveshapes and dimensions is stopped at a position corresponding to thecenter of the range of movement of the component mounting head 230 movedby the XY robot 266, in the conveying direction of the PWB conveyor 14,so that the electronic circuit components 16 are mounted on the PWB 12stopped there. That is, the PWB 12 is stopped such that the center ofthe PWB 12 in the direction parallel to the conveying direction islocated at the center of the range of movement of the component mountinghead 230 moved by the XY robot 266 in the conveying direction.Hereinafter, the center of the range of the movement of the componentmounting head 230 in the conveying direction of the PWB conveyor 14 willbe referred to as a “center position in the conveying direction”. ThePWB 12 can be conveyed in both of the forward and reverse directions bythe PWB conveyor 14, and is stopped at the center position in theconveying direction whether the conveying direction is forward orreverse. The stop position of the PWB 12 is set with respect to thecenter of the PWB 12 in the direction parallel to the conveyingdirection. Upon detection of the downstream-side edge of the PWB 12 byone of the photoelectric sensors 310, 312 which one is located on theupstream side in the conveying direction, the conveyance of the PWB 12is decelerated, and upon detection of the downstream-side edge of thePWB 12 by the other of the photoelectric sensors 310, 312 which islocated on the downstream side in the conveying direction, the PWB 12 isstopped. The upstream photoelectric sensor functions as a decelerationsensor, while the downstream photoelectric sensor functions as a stopsensor.

In the case where the downstream-side edge of the PWB 12 in theconveying direction is detected as the predetermined detection portionso as to detect the PWB 12 for stopping the PWB 12 at the centerposition in the conveying direction, the position of the downstream-sideedge of the PWB 12 in the conveying direction when the PWB 12 is stoppedvaries depending upon the shape and dimensions of the PWB 12 conveyed,and the locations where the photoelectric sensors 310, 312 which detectthe PWB 12 should be positioned also vary. Hence, the locations to whichthe X-axis and Y-axis slides 236, 252 should be respectively moved tohave the photoelectric sensors 310, 312 detect the PWB 12, whichlocations correspond to the detection location at which the PWB detector308 operates to detect the downstream-side edge of the PWB 12, arepredetermined depending upon the shape and dimensions of the PWB 12 andthe conveying direction. That is, locations of the X-axis and Y-axisslides 236, 252 are predetermined such that the PWB detector 308 ispositioned at the location where the downstream-side edge of the PWB 12is positioned, in the state where the PWB 12 is stopped at the centerposition in the conveying direction, so that the photoelectric sensors310, 312 detect the downstream-side edge. The locations to which theX-axis and Y-axis slides 236, 252 should be respectively moved arestored in the PWB detection location data memory, with being associatedwith the kind of PWB 12 and the conveying direction. The plurality ofkinds of PWBs 12 are assigned with respective codes, and datarepresentative of the codes are stored in the PWB detection locationdata memory, as well as data indicative of locations to which the X-axisand Y-axis slides 236, 252 should be moved and data indicative of theconveying directions.

In the first embodiment, the locations of the photoelectric sensors 310,312 in the Y-axis direction at the time when the detection of the PWB 12is made are constant and predetermined such that the photoelectricsensors 310, 312 can detect the PWB 12 irrespective of the shape anddimensions of the PWB 12 and the conveying direction, and the locationof the Y-axis slide 252 moving the photoelectric sensors 310, 312 torespective detection locations where to detect the PWB 12 is madeconstant irrespective of the kind of the PWB 12. A distance between thefirst and second photoelectric sensors 310, 312 is determined to besufficient to appropriately decelerate the PWB 12 upon a detectionthereof and stop the PWB 12 in the decelerated state.

As described above, location-related information pertaining to thelocations to which the X-axis and Y-axis slides 236, 252 should be movedso that the photoelectric sensors 310, 312 detect the predetermineddetection portion of the PWB 12 includes data defining the locations towhich the X-axis and Y-axis slides 236, 252 are to be moved. In thefirst embodiment, such location-related information varies dependingupon dimensions and shape of the PWB 12 and the conveying direction, andis used for stopping the PWB 12 at the center position of the range ofmovement of the component mounting head 230 moved by the XY robot 266 inthe conveying direction of the PWB conveyor 14.

There will be described operation of the system 11.

When to mount the electronic circuit components 16 on the PWB 12, thePWB 12 is conveyed into the system 11 by the PWB conveyor 14, and thedownstream-side edge of the PWB 12 is detected by the photoelectricsensors 310, 312 and the PWB 12 is stopped at the center position in theconveying direction. It is noted that when the PWB supporting device isreset, i.e., when the PWB 12 on which the electronic circuit components16 is are to be mounted is changed to a PWB 12 of another kind, thedistance between the pairs of the guides 110, 112 and conveyor belts 124is changed, if needed, by the interval changing device 214 prior to theinitiation of the mounting the electronic circuit components 16 on thePWB 12 of another kind, so as to be suited to the width of the anotherkind of PWB 12.

The control of stopping the PWB 12 will be described by reference toFIGS. 11-14.

When the PWB 12 is carried onto the PWB conveyor 14 to be conveyed bythe PWB conveyor 14, the XY robot 266 is controlled such that the firstand second photoelectric sensors 310, 312 are moved to the predetermineddetection locations where to detect the downstream-side edge of the PWB12 so that the PWB 12 is stopped at the center position in the conveyingdirection, prior to that the PWB 12 reaches the stop position which isthe central position in the conveying direction. Namely, the locationsto which the X-axis and Y-axis slides 236, 252 should be respectivelymoved, which locations are predetermined depending upon the kind andconveying direction of the PWB 12 so that the photoelectric sensors 310,312 are moved to the respective predetermined detection locations, areread from the RAM 358, and the X-axis and Y-axis moving motors 240, 256are controlled based on the detection signals from the encoders 368, 370so that the X-axis and Y-axis slides 236, 252 are moved to thepredetermined locations, to move the photoelectric sensors 310, 312 tothe respective predetermined detection locations. The light emittingelement 314 of each sensor 310, 312 radiates a light which is to bedetected by the light receiving element 16, for thereby detecting thePWB 12. The XY robot 266 has a drive source in the form of a servomotor,and is constructed such that the component mounting head 230 is movedaccurately to the predetermined location so that the electronic circuitcomponents 16 can be mounted on the PWB 12 with high accuracy. Thus, thePWB detector 308 is accurately moved to the detection location, therebyimproving accuracy of the control of stopping the PWB 12.

In the case where the PWB 12 is conveyed rightward direction as seen inFIG. 11 (i.e. the direction as indicated by a solid arrow), thephotoelectric sensors 310, 312 are moved to the locations as indicatedby solid lines in FIG. 11, which locations are on the downstream sidewith respect to the central position in the conveying direction and atwhich locations the first photoelectric sensor 310 is on the upstreamside in the conveying direction with respect to the second photoelectricsensor 312. When the PWB 12 approaches its stop position and thedownstream edge of the PWB 12 reaches a position under the firstphotoelectric sensor 310, the light radiated from the light emittingelement 314 of the first photoelectric sensor 310 is reflected by thedownstream-side edge of the PWB 12 and received by the light receivingelement 316, thereby detecting the downstream-side edge of the PWB 12,i.e., detecting that the PWB 12 has been conveyed to the vicinity of thestop position. Based on this detection, an instruction for deceleratingthe conveyance of the PWB 12 is issued so that the rotational velocityof the PWB conveyor motor 142 is decreased to decelerate the conveyanceof the PWB 12.

The downstream-side edge of the PWB 12 conveyed at the lowered speedeventually reaches the position under the second photoelectric sensor312, and the light radiated from the light emitting element 314 isreflected by the downstream-side edge of the PWB 12 and received by thelight receiving element 316, to thus detect the PWB 12. Then, a stopinstruction is issued so that the PWB 12 is stopped at the centerposition in the conveying direction.

In the case where the PWB 12 is conveyed leftward direction as seen inFIG. 11 (i.e. the direction as indicated by an arrow of chaindouble-dashed line), the photoelectric sensors 310, 312 are moved to thelocations as indicated by chain double-dashed lines in FIG. 11, whichlocations are on the downstream side with respect to the centralposition in the conveying direction, and which are opposite, withrespect to the center position of conveying directions, to thecorresponding locations of the photoelectric sensors 310, 312 in thecase where the PWB 12 is conveyed rightward. The second photoelectricsensor 312 is positioned on the upstream-side in the conveying directionwith respect to the first photoelectric sensor 310 and functions as thedeceleration sensor, while the second photoelectric sensor 312 functionsas the stop sensor, so that the conveyance of the PWB 12 is deceleratedand then stopped.

The first and second photoelectric sensors 310, 312 detect the PWB 12while positioned at the respective locations which are predetermineddepending upon the dimensions and shape of the PWB 12. Therefore, in thecase where the PWB 12 is small-sized, an interval between the pair ofguides 110, 112 is changed in accordance with the width of the PWB 12,as well as the first and second photoelectric sensors 310, 312 are movedto respective locations corresponding to the dimension of the PWB 12 inthe direction parallel to the conveying direction, such that thedownstream-side edge of the PWB 12 is detected so that the PWB 12 isdecelerated and then stopped, as schematically shown in FIG. 12, forexample.

In another case where the PWB 12 has a cutout 386 at its downstream-sideedge in the conveying direction, as shown in FIG. 13, the first andsecond photoelectric sensors 310, 312, which are respectively located atthe same positions in a direction perpendicular to the conveyingdirection as in the case where the PWB 12 does not have such a cutout386, can detect the PWB 12 which is stopped at the center position inthe conveying direction. As described above, in the first embodiment,the locations of the photoelectric sensors 310, 312 in the Y-axisdirection at the time of detecting the PWB 12 are constant irrespectiveof the dimensions, shape and conveying direction of the PWB 12. Even ina case where these constant locations in the Y-axis direction areidentical with the position in the Y-axis direction of the cutout 386 ofthe PWB 12 as conveyed by the PWB conveyor 14, it is possible to detectthe PWB 12 and stop the PWB 12 at the center position in the conveyingdirection, by properly setting the detection locations of thephotoelectric sensors 310, 312 in the X-axis direction which is parallelto the conveying direction.

The PWB 12 having the cutout 386 is stopped such that a point on the PWB12, which is the center of the PWB 12 in the conveying direction whenassuming that the PWB does not have the cutout 386, is positioned at thecenter position in the range of movement of the component mounting head230 in the conveying direction of the PWB conveyor 14. Hence, thelocation to which the X-axis slide 236 is to be moved is predeterminedsuch that where the PWB 12 is stopped in the state as described above,the PWB detector 308 is located at the position corresponding to theedge which has the cutout 386 and is perpendicular to the conveyingdirection, and that the photoelectric sensors 310, 312 detect the edgehaving the cutout 386 and corresponding to the downstream-side edge. Theposition to which the Y-axis slide 256 is to be moved is predeterminedin the same way as in the case where the PWB 12 does not have the cutout386.

Alternatively, the position of the PWB detector 308 in the direction(Y-axis direction) perpendicular to the conveying direction may bedifferentiated from that in the case where the PWB 12 without the cutout386 is detected, so that the first and second photoelectric sensors 310,312 detect a portion of the PWB 12 other than the cutout 386. In eithercase, by properly predetermining the detection locations of the firstand second photoelectric sensors 310, 312, the PWB 12 with the cutout386 can be stopped at the center position in the conveying directionbased on the detection by the sensors 310, 312, as well as theelectronic circuit components 16 can be mounted on the PWB 12, in thesame way as in the case where the PWB 12 does not have the cutout.

Irrespective of what shape and dimensions the PWB 12 has and whether theconveying direction is forward or reverse, once the PWB 12 is conveyedby the PWB conveyor 14 to be stopped at the center position in theconveying direction, based on the detection of the PWB 12 by thephotoelectric sensors 310, 312, the electronic circuit components 16 aremounted on the stopped PWB 12 by the component mounting head 230. Afterbeing stopped, the PWB 12 is supported by the PWB supporting device 15from the under side, as well as clamped by the PWB clamp device. Then,the fiducial-mark camera 294 is moved by the XY robot 266 and takes animage of the fiducial mark 290 to detect the position of the PWB 12, andrespective horizontal position errors of a plurality of prescribedmounting points on the surface 180 are obtained by computing. Then theXY robot 266 moves the component mounting head 230, which receives theelectronic circuit component 16 from the component supplying device 20and mounts the component 16 on the PWB 12 at the prescribed mountingpoint.

When the component mounting head 230 receives the electronic circuitcomponent 16 from the component supplying device 20, the suction nozzle282 suctions the electronic circuit component 16 positioned at thecomponent supply portion of one of the feeders 30. Suctioning thecomponent 16, the component mounting head 230 is moved by the XY robot266 toward the mounting point on the PWB 12. During this movement, thecomponent mounting head 230 is stopped at a position above the lightguiding device 338 of the component imaging system 330 in the X-axisdirection, where an image of the electronic circuit component 16 istaken by the component camera 336. Since the component imaging system330 is disposed on the X-axis slide 236, the component mounting head 230necessarily passes above the light guiding device 338 on the way fromthe component supplying device 20 to the PWB 12 and thus the image ofthe electronic circuit component 16 can be taken. On the basis of thedata of the image, a holding-position error (horizontal position errorand rotational position error) of the electronic circuit component 16 isdetected. The component mounting head 230 is rotated by the headrotating device 272 so that the rotational position error of theelectronic circuit component 16 is corrected, while the distance ofmovement of the component mounting head 230 is corrected so that adeviation of the center position of the electronic circuit component 16from a nominal position, which deviation is caused by correcting theholding-position error, the horizontal position error of the mountingpoint on the PWB 12 and the rotational position error. Electroniccircuit component 16 is then mounted on the PWB 12. Thus, one cycle ofmounting operation is terminated.

The locations to which the X-axis and Y-axis slides 236, 252 are to bemoved are predetermined so as to move the photoelectric sensors 310, 312to the predetermined detection locations, and the PWB 12 can be stoppedat the center position in the conveying direction irrespective of theshape, dimensions and the conveying direction of the PWB 12, asdescribed above. Therefore, the PWB 12 and the component supplyingdevice 20 are located at the center position in the conveying direction,making the respective center positions coincident with each other. Thus,the distance of required movement of the component mounting head 230 inmounting the component can be reduced, improving a probability that themounting operation is performed efficiently. In other words, aprobability that the total distance of movement of the componentmounting head 230 required to mount all electronic circuit components 16on the PWB 12 is smaller than in the case where the center positions ofthe PWB 12 and the component supplying device 20 do not coincide witheach other, is high. Particularly, in the case where the PWB 12 issmall-sized and therefore is stopped in the marginal portion(downstream-side edge) of the range of movement of the componentmounting head 230 such that the PWB 12 is significantly deviated fromthe central portion of the component supplying device 20 in thedirection parallel to the conveying direction, the probability that thetotal distance of movement of the component mounting head 230 isincreased is high. However, according to the arrangement where the PWB12 is positioned at the center position in the conveying direction, evenin the case where the PWB 12 is small-sized, the PWB 12 is stopped atthe location adjacent to the center position of the component supplyingdevice 20 in the conveying direction, thereby improving the probabilitythat the mounting operation is performed with high efficiency.

In another operational mode of the present electronic-circuit-componentmounting system 11, the component supplying device 20 is adapted tosupply electronic circuit components 16 to a plurality of kinds of thePWBs 12. For instance, in a case where: the PWB is small-sized; thenumber of kinds of electronic circuit components 16 to be mounted issmall; and the number of sorts of printed circuit boards to be producedis large while the number of lots of the PWBs 12 is small, if a sum ofnumbers of feeders 30 required to mount the electronic circuitcomponents 16 on the respective kinds of PWBs 12 becomes a numberpossible to place on the feeder support table 32, the componentsupplying device 20 can supply electronic circuit components 16 to theplurality of kinds of PWBs 12. That is, the component supplying device20 is adapted to mount electronic circuit components 16 on PWBs 12according to a plurality of kinds of mounting programs.

For instance, in a case where the component supplying device 20 iscapable of supplying electronic circuit components 16 on two kinds ofPWBs 12, a group of feeders 30 for supplying electronic circuitcomponents 16 to particular one of two kinds of PWBs 12 is disposed onone of opposite sides of the feeder support table 32 in the conveyingdirection, while another group of feeders 30 for supplying electroniccircuit components 16 to the other kind of PWB 12 is disposed on theother side, as schematically shown in FIG. 14. That is, a plurality of(two in this case) feeder groups 390, each comprising a multiplicity offeeders 30 for supplying electronic circuit components 16 to aparticular kind of PWB 12, are placed on the feeder support table 32 ina row extending in a direction parallel to the conveying direction.

The stop position of the PWB 12 is predetermined in accordance with thekind of the PWB 12. For example, the stop positions of the respectivekinds of the PWBs 12 are determined to be adjacent, in the directionperpendicular to the conveying direction, to the respectivelycorresponding feeder groups 390 for supplying the electronic circuitcomponents 16 to the respective kinds of the PWBs. Further, in thepresent mode of the first embodiment, the center position of the PWB 12in the conveying direction is predetermined to be coincident with thecenter position of the relevant feeder group 390 in the directionparallel to the conveying direction, and is stored as PWB stop positiondata in a PWB stop position data memory in the RAM 358 with beingassociated with the type of the PWB 12. That is, in this arrangement,the stop position is predetermined at a center position in a directionparallel to the conveying direction. To stop the plurality of types ofPWBs 12 at respective predetermined stop positions based on the PWB stopposition data, locations to which the X-axis and Y-axis slides 236, 252should be moved to displace the photoelectric sensors 310, 312 to therespective detection locations, are predetermined on the basis of shapesand dimensions of the respective types of PWBs 12 and the conveyingdirections, and stored in the PWB detection location data memory withbeing associated with the kinds of the PWBs 12, along with data definingthe conveying direction in association with the types of the PWBs 12. Inthis specific case, the predetermined detection portion of the PWB 12 isthe downstream-side edge of the PWB 12 in the conveying direction, andlocations to which the X-axis and Y-axis slides 236, 252 should be movedis predetermined such that, where the PWB 12 is stopped at the stopposition, the PWB detector 308 is placed at a location corresponding tothe position of the downstream-side edge so that the photoelectricsensors 310, 312 detect the downstream-side edge, and the thuspredetermined locations are stored in the PWB stop position data memory.In a case where the conveying direction is fixed to a particulardirection, it is not necessary to store the data defining the conveyingdirection.

In conveying the PWB 12 on the PWB conveyor 14, the photoelectricsensors 310, 312 are moved by the XY robot 266 to the respectivepredetermined detection locations in accordance with conditionsincluding the type of the PWB 12, and detect the downstream-side edge ofthe PWB 12 to decelerate and then stop the PWB 12. Thus, the PWB 12 isstopped at a position adjacent to, in the direction perpendicular to theconveying direction, one of the feeder groups 390 which supplieselectronic circuit components 16 to the type of PWB 12, in whichposition the center positions of the PWB 12 and the feeder group 390 inthe conveying direction coincide with each other.

In the arrangement where the single component supplying device 20supplies electronic circuit components 16 to a plurality of types ofPWBs 12, it is not necessary to replace the feeder 30 each time the typeof the PWB 12 is changed, but merely the stop position of the PWB 12 ischanged, thereby enabling an efficient mounting operation involvingchanges in the type of PWBs 12. Since each PWB 12 is stopped at aposition which is adjacent, in the direction perpendicular to theconveying direction, to the feeder group 390 which supplies the PWB 12with electronic circuit components 16, and at which the center positionsof the PWB 12 and the feeder group 390 coincide with each other, thedistance of movement of the component mounting head 230 is reduced,thereby enabling the efficiently mounting the electronic circuitcomponents 16.

As apparent from the above description, in the first embodiment, the PWBdetection location data memory and the PWB stop position data memoryconstitute a memory, while the controller 350 constitutes a substratestop position controller.

The PWB stop position data memory may be omitted, since an arrangementwhere: the locations to which the X-axis and Y-axis slides 236, 252should be respectively moved are predetermined based on thepredetermined stop positions corresponding to the types of PWBs 12 suchthat the photoelectric sensors 310, 312 are moved to the locations whereto detect the predetermined detection portion of the PWB 12; and suchlocations to which the X-axis and Y-axis slides 236, 252 should berespectively moved are stored with being associated with the types ofthe PWBs 12, can be considered to be equal to that the stop positionsare stored with being associated with the respective types of PWBs 12.

In the above-described first embodiment, the component imaging system330 is disposed on the X-axis slide 236. However, the component imagingsystem 330 may be disposed such that the location of the system 330 isfixed. Such an embodiment (second embodiment) will be described byreference to FIG. 15. The same reference numerals as used in the firstembodiment are used to designate the corresponding elements of thesecond embodiment and the description thereof is omitted.

In an electronic-circuit-component mounting system 400 according to thesecond embodiment, a component imaging system 402 is disposed with itslocation fixed, at a position which is between a component supplyingdevice 20 and a PWB conveyor 14, and which is a center position of arange of movement of a component mounting head 230 in the direction inwhich the PWB conveyor 14 conveys the PWB 12. That is, the componentimaging system 402 is located at a position corresponding to a centerposition of a row of component supply portions of a plurality of feeders30. The component imaging system 402 has a component camera 404 as animaging device and a lighting device 406, is located below a plane ofmovement of the component mounting head 230, and operates to take afront elevational image and a projective image of an object.

When the PWB 12 is stopped at the center position in the conveyingdirection, an entirety of the PWB 12 is positioned in the vicinity ofthe component imaging system 402, thereby improving a probability that atotal distance of the movement of the component mounting head 230 isreduced and therefore the mounting operation is performed efficiently.After receiving the electronic circuit component 16 and prior to themounting of the electronic circuit component 16 on the PWB 12, thecomponent mounting head 230 is necessarily moved to a locationcorresponding to the component imaging system 402 so that an image ofthe electronic circuit component 16 is taken. Since the componentimaging system 402 and the PWB 12 are made adjacent to each other in ahorizontal direction perpendicular to the conveying direction, theprobability that the total distance of movement of the componentmounting head 230 after the imaging operation and during the movementtoward the PWB 12 can be reduced, is improved.

For instance, a case where a stop position of the PWB 12 ispredetermined such that a downstream-side edge of the PWB 12 is locatedat a constant position irrespective of the type of the PWB 12 isconsidered here. In this case, when the stop position of the PWB 12 ispredetermined on the basis of a large-sized PWB 12, if the PWB 12 inquestion has a small size, the PWB 12 is stopped in a marginal portionof the range of movement of the component mounting head 230, asindicated by a chain double-dashed line in FIG. 15. In such a case, adistance between the PWB 12 and the component imaging system 402 andaccordingly a time required for the movement of the component mountinghead 230 are adversely longer than in a case where the PWB 12 is stoppedat the center position in the conveying direction, that is, at aposition adjacent to the component imaging system 402 in the directionperpendicular to the conveying direction. On the other hand, accordingto the electronic-circuit-component mounting system 404 of the secondembodiment, the PWB 12 is stopped such that the entirety of the PWB 12is located adjacent to the component imaging system 402, irrespective ofthe type of the PWB 12. Hence, even in the case where the PWB 12 issmall-sized, a distance of waste movement of the component mounting head230 is reduced, shortening the total distance of the movement of thecomponent mounting head 230, and thereby enhancing the efficiency of themounting operation.

In the embodiments described above, the predetermined detection portionof the PWB 12 is detected by the photoelectric sensors and then the PWB12 is stopped. However, the detection may be implemented by taking animage with an imaging device, after which the PWB 12 is stopped. Such anembodiment (third embodiment) will be described by reference to FIGS.16-18.

Except the control of stopping the PWB 12, anelectronic-circuit-component mounting system 420 according to the thirdembodiment is constructed similarly to the electronic-circuit-componentmounting system 11 as described above, and the similar part is notdescribed here.

In the third embodiment, a fiducial-mark camera 294 of a fiducial-markimaging system 292 takes an image of a downstream-side edge of a PWB 12in a conveying direction so that the PWB 12 is detected, decelerated andstopped. That is, the imaging device for taking an image of apredetermined detection portion of the PWB 12 is adapted to take animage of the fiducial mark 290 provided on a surface 180 of the PWB 12,and thereby acts as a fiducial-mark imaging device for detecting thestop position of the PWB 12.

In the third embodiment, too, the PWB 12 is stopped at a center positionin the conveying direction, and locations to which the X-axis and Y-axisslides 236, 252 should be moved to have the fiducial-mark camera 294detect the downstream-side edge of the PWB 12 and fiducial mark 290 arepredetermined depending upon dimensions, a shape and a conveyingdirection of the PWB 12, and the predetermined locations are stored in aPWB detection location data memory.

Each of the locations to which the X-axis and Y-axis slides 236, 252should be moved consists of two locations: one of which is a location tohave the fiducial-mark camera 294 take the image of the downstream-sideedge of the PWB 12; and the other is a location to have thefiducial-mark camera 294 take the image of the fiducial mark 290. Theformer location is a first detection location of the fiducial-markcamera 294, for decelerating the PWB 12, while the latter location is asecond detection location for stopping the PWB 12. The second detectionlocation is determined to correspond to a center of the fiducial mark290 in a state where the PWB 12 is stopped at the center position in theconveying direction. The first detection location is determined to be onthe upstream side with respect to the second detection location in theconveying direction. The distance between the first and second detectionlocations is determined such that, after imaging the downstream-sideedge of the PWB 12 so that the PWB 12 is detected and a decelerationinstruction is issued, the fiducial-mark camera 294 which is moved at aspeed higher than that of the PWB 12 can reach the second detectionlocation before the PWB 12 reaches the second detection location.

When the PWB 12 is carried into the system 11 by the PWB conveyor 14,the locations to which the X-axis and Y-axis slides 236, 252, should bemoved which locations are predetermined depending upon the type of thePWB 12 and a conveying direction, are read out, and the fiducial-markcamera 294 is first moved to the first detection location. Morespecifically described, the X-axis and Y-axis slide moving motors 240,256 are controlled based on outputs of encoders 368, 370, and thefiducial-mark camera 294 is moved to such a location that an imagecenter as a center of an imaging area or imaging screen is located atthe first detection location. The first lighting device 296 performs itslighting operation while the fiducial-mark camera 294 implements imagetaking operations at a preset time interval.

In the third embodiment, the first lighting device 296 is adapted tostepwise adjust a luminance of a light (by two steps in this specificexample), and when the fiducial-mark camera 294 takes the image at thefirst detection location, a lighting operation with a light of the lowerluminance is implemented, since the timing of the downstream-side edgeof the PWB 12 reaching the deceleration position at which the edge issubjected to the image-taking operation is unknown and the lightingoperation continues until the image-taking operation is performed. Eachtime the fiducial-mark camera 294 takes an image, data of the takenimage is processed by an image processing computer 366, and adetermination as to whether the downstream-side edge of the PWB 12 inthe conveying direction is detected is made by the computer 352. In acase where the downstream-side edge of the PWB 12 has entered into theimaging area and is subjected to the imaging operation by thefiducial-mark camera 294, an image of the downstream-side edge is formedin the imaging area, as indicated by hatching in FIG. 17, meaning thatthe edge is detected. Then, the deceleration instruction is output so asto decelerate the conveyance of the PWB 12.

The fiducial-mark camera 294 is moved to the second detection locationas indicated by a chain double-dashed line in FIG. 16, and the lightingdevice performs a lighting operation with a light of the higherluminance. The fiducial-mark camera 294 implements image takingoperations at a preset time interval. More specifically described, thefiducial-mark camera 294 is moved by the XY robot 266 at a speed higherthan that of the PWB 12, to reach a stop-position detection locationbefore the PWB 12 reaches the stop position. Namely, the fiducial-markcamera 294 is moved to a position where the imaging center of thefiducial-mark camera 294 is located at the stop-position detectionlocation.

The fiducial-mark camera 294 repeats imaging operations at the presettime interval, and the image data are processed so that thedetermination as to whether the PWB 12 has reached the stop position ismade. Once the fiducial mark 290 has entered into the imaging area, eachtime the fiducial-mark camera 294 implements the image-taking operation,an image of the fiducial mark 290 is captured, as indicated by chainsingle-dashed and double-dashed lines in FIG. 18. When the image of thefiducial mark 290 is formed at a predetermined position, which is, inthis specific example, when the image of the fiducial mark 290 is formedsuch that the center thereof is located within a range of apredetermined distance from the center of the imaging area, it isdetermined that the PWB 12 has reached the stop position, and a stopinstruction is output. That is, even if the center of the image of thefiducial mark 290 does not coincide with the center of the imaging area,as long as the image of the fiducial mark 290 is formed at a positionsuch that the PWB 12 can be considered as has reached the stop position,the PWB 12 is considered to have reached the stop position, and isstopped. After the stopping of the PWB 12, the fiducial-mark camera 294again takes an image of the fiducial mark 290, while remaining at thestop-position detection location. An actual stop position of the PWB 12is accurately detected on the basis of the data of the taken image, andthe detected stop position is used for calculation of a horizontalposition error of the mounting point.

In the third embodiment, the fiducial-mark imaging system 292 isemployed for the control of stopping the PWB 12, making the stop controleconomical. Further, since the fiducial-mark camera 294 can take animage of the fiducial mark 290 to detect the stop position of the PWB 12while the fiducial-mark camera 294 is located at the positioncorresponding to the position where the PWB 12 is stopped, it is enabledto quickly detect the location of the PWB 12.

In each of the above-described embodiments, the PWB is detected by asubstrate detector of non-contact type, and is then stopped. However,the PWB may be stopped by being brought into abutting contact with astopper. Such an embodiment (fourth embodiment) will be described byreference to FIG. 19. The same reference numerals as used in theabove-described embodiments are used to designate the correspondingelements of the fourth embodiment and the description thereof isomitted.

As shown in FIG. 19, in an electronic-circuit-component mounting system500 according to the fourth embodiment, a Y-axis slide 252 of the XYrobot 266 holds a component mounting head 230, a fiducial-mark imagingsystem 292, a stopper 502 and a stopper lifting/lowering device 504 as astopper moving device, and is moved by the XY robot 266 to a desiredposition in the X-Y coordinate plane. In the fourth embodiment, thestopper lifting/lowering device 504 includes an air cylinder 506 as ahydraulic actuator as a drive source, which has a piston rod 508 havinga lower end on which a stopper 502 is disposed. With an axial movementof the piston rod 508, the stopper 502 is moved to an operative positionwhich is in a path of conveyance of the PWB 12, and to an inoperativeposition deviated from the path of conveyance.

The Y-axis slide 252 further holds a photoelectric sensor 510 as anarrival detector for detecting that the PWB 12 has reached the positionwhere the PWB 12 is to be brought into contact with the stopper 502. Thephotoelectric sensor 510 is a kind of non-contact type detector. In thefourth embodiment, the photoelectric sensor 510 is constituted by areflection-type detector which comprises a light emitting element 512and a light receiving element 514, and which is positioned adjacent tothe stopper 502 in the direction perpendicular to the conveyingdirection in the plane of the conveyance. The photoelectric sensor 510is positioned in the conveying direction such that the sensor 510 candetect the downstream-side edge of the PWB 12 in the conveying directionwhile the PWB 12 is held in contact with the stopper 502 (i.e., in astate where the PWB 12 is stopped at a predetermined stop position). Inthe fourth embodiment, the light emitting element 512 and lightreceiving element 514 are disposed next to each other in the directionperpendicular to the conveying direction in the plane. Similar to theelectronic-circuit-component mounting system 11, theelectronic-circuit-component mounting system 500 is controlled by acontroller which is mainly constituted by a computer, and an outputsignal from the photoelectric sensor 510 is input into the computer. Theair cylinder 506 is controlled by the controller.

In the fourth embodiment also, in the case where the PWB 12 is stoppedat the central position in the conveying direction, the locations towhich the X-axis and Y-axis slides 236, 252 should be moved so that thestopper 502 is brought into contact with the PWB 12 to stop the PWB 12are predetermined depending upon the dimensions and shape of the PWB 12,and the thus predetermined locations are stored in a PWB detectionlocation data memory, with being associated with the type of the PWB 12.In the fourth embodiment, the direction of conveyance of the PWB 12 isfixed to one direction.

In carrying in the PWB 12 into the system 500 by the PWB conveyor 14,the stopper 502 is moved by the XY robot 266 to a predetermined positionwhich is a position where the PWB 12 is stopped by being brought intocontact with the PWB 12, and is lowered by the stopper lifting/loweringdevice 504 to an operative position. In the photoelectric sensor 510,the light emitting element 512 radiates a light. Thus, the PWB 12 whichis conveyed by the PWB conveyor 14 and reaches the stop position isbrought into contact with the stopper 502 and is stopped. In this state,the light radiated from the light emitting element 512 is reflected bythe PWB 12 and received by the light receiving element 514. Thus, thePWB 12 is detected by the photoelectric sensor 510, and a stopinstruction is issued on the basis of the detection, so that a PWBconveyor motor 142 of the PWB conveyor 14 is stopped. In the fourthembodiment, the controller constitutes a conveyor controller.

The present invention is applicable to an adhesive applying system as akind of a working system for a circuit substrate, in the form of ahighly-viscous fluid applying system. Such an embodiment (fifthembodiment) will be described by reference to FIGS. 20 and 21. Theadhesive applying system 550 according to the fifth embodiment isconstructed similarly to the adhesive applying system as described inunpublished Japanese Patent Application No. 2001-001983 by the presentapplicant, except the control of stopping the PWB, and is therefore onlybriefly described.

On a base 552 of the adhesive applying system 550, there are disposed ahighly-viscous fluid applying device in the form of an adhesive applyingdevice 554, and a PWB conveyor 558 for conveying a PWB 556 as a kind ofcircuit substrate which is an object for applying a highly-viscousfluid. The PWB conveyor 558 is constructed similarly to the PWB conveyor14 of the above-described embodiments, has a stationary guide 560 and amovable guide 562. More specifically, the PWB conveyor 558 is a beltconveyor in which a pair of endless conveyor belts is circulated insynchronization with each other by being driven by a PWB conveyor motor(not shown), so that the PWB 556 is conveyed in an X-axis direction inan X-Y coordinate plane as being set over the entirety of the adhesiveapplying system 550. The PWB conveyor 558 is capable of being stopped ata desired position in its conveying direction, and can be conveyed inboth of forward and reverse directions. A distance between pairs ofconveyor belts (not shown) and the guides 560, 562 is changeable by aninterval changing device. In the midstream of a path of the conveyance,there are disposed a PWB supporting device for supporting the PWB 556from the under side, and a PWB holding device including a PWB clampdevice for clamping the PWB 556, although these devices are not shown inthe drawings.

The adhesive applying device 554 has an XY robot 568 as a moving device,and moves a applying unit 570 in a direction having an X-component and aY-component which are perpendicular to each other in the X-Y coordinateplane, so that the applying unit 570 is located at a desired position ina plane parallel to an application surface as an upper surface of thePWB 556, where the applying unit 570 applies the adhesive in the form ofspots on the application surface.

As shown in FIGS. 20 and 21 and similarly to the above-described XYrobot 266, the XY robot 568 includes: an X-axis slide moving device 580including an X-axis slide 572, an X-axis slide moving motor 574, ballscrews 576 and nuts 578; and a Y-axis slide moving device 592 includinga Y-axis slide 584, a Y-axis slide moving motor 586, a ball screw 588and a nut (not shown). The X-axis slide 572 constitutes a first movablemember, while the Y-axis slide 584 constitutes a second movable member.These X-axis and Y-axis slides 572, 584 and X-axis and Y-axis slidemoving devices 580, 592 constitute the XY robot 568. Movement of theX-axis slide 572 is guided by an X-axis guiding device comprising a pairof guide rails 596 and a pair of guide blocks 598 guided by the guiderails 596, while movement of the Y-axis slide 584 is guided by a Y-axisguiding device comprising a pair of guide rails 600 and a pair of guideblocks 602. The ball screws 576, 588 and nuts 578 constitute a motiontransmitting mechanism. In this fifth embodiment, each of the X-axisslide moving motor 574 and Y-axis slide moving motor 586 each as a drivesource, consists of a servo motor.

The applying unit 570 is held by the Y-axis slide 584 such that theapplying unit 570 can be lifted/lowered by an applying unitlifting/lowering unit 614 including a Z-axis slide 610 and a Z-axisslide lifting/lowering device 612 as a Z-axis slide moving device, so asto be moved toward and away from the PWB 556. The applying unit 570 has,for example, a discharge nozzle 620, a nozzle rotating device, a screwpump, a screw rotating device, and an adhesive supplying device as ahighly-viscous fluid supplying device, although these devices are notshown and not described. In the fifth embodiment, the applying unit 570constitutes a working head, and is adapted such that a predeterminedamount of the adhesive is ejected from the discharge nozzle 620 byrotation of a screw or screws, to be applied to an application point onthe PWB 556. The applying unit may be adapted such that an adhesiveaccommodated in a syringe is discharged by a pressure of a compressedair, to be applied on the PWB 556.

A fiducial-mark imaging system 626 for taking an image of a fiducialmark 624 on the PWB 556 is provided on the Y-axis slide 584. Thefiducial-mark imaging system 626 includes a fiducial-mark camera 628 anda lighting device (not shown). The Y-axis slide 584 further holds a PWBdetector 640, which has a first photoelectric sensor 642 and a secondphotoelectric sensor 644, similarly to the PWB detector 308. Each of thephotoelectric sensors 642, 644 has a light emitting element 646 and alight receiving element 648, and the sensors 642, 644 are aligned withand spaced from each other in the direction parallel to the conveyingdirection. The light emitting element 646 and the corresponding lightreceiving element 648 are also aligned with and spaced from each otherin the direction parallel to the conveying direction.

The adhesive applying system 550 is controlled by a controller 650(shown in FIG. 20) which is principally constituted by a computer.

In the fifth embodiment, the PWB detector 640 detects the PWB 556,similarly to the PWB detector 308. For instance, a downstream-side edgeof the PWB 556 in the conveying direction is selected as a predetermineddetection portion, and one of the photoelectric sensors 642, 644 whichis positioned upstream with respect to the other sensor detects thedownstream-side edge as the predetermined detection portion. Upondetection of the downstream-side edge, the conveyance of the PWB 556 isdecelerated. When the other of the two sensors 642, 644 which ispositioned downstream detects the downstream-side edge, the PWB 556 isstopped.

For example, in the adhesive applying system 550, the stop position ofthe PWB 556 is determined depending upon the type of the PWB 556 and theconveying direction, and the determined stop position is stored in a PWBstop position data memory (not shown) in a RAM of the computer, withbeing associated with the type of the PWB 12 and the conveyingdirection. For instance, the stop position of the PWB 556 is determinedwith respect to the center position of the PWB 556 in the directionparallel to the conveying direction, and may be varied depending uponthe type of the PWB 556, such that the center position in the directionparallel to the conveying direction is differentiated depending upon thetype of the PWB 556.

The location of the PWB detector 640 where the PWB detector 640 detectsthe predetermined detection portion is determined depending upon thestop position of the PWB 556. In the fifth embodiment, in a state wherethe PWB 556 is stopped at the stop position, a position where thedownstream-side edge of the PWB 556 is located is the detectionlocation, and locations of the X-axis and Y-axis slides 572, 584 arepredetermined so that the PWB detector 640 is placed at a positioncorresponding to the detection location, and the photoelectric sensors642, 644 detect the downstream-side edge of the PWB 556. The thusdetermined locations of the X-axis and Y-axis slides 572, 584 are storedin a PWB detection location data memory (not shown), with beingassociated with the type of the PWB 556 and the conveying direction.

In conveying the PWB 556, before the PWB 556 reaches the stop position,the PWB detector 640 is moved by the XY robot 568 to the predetermineddetection location. When the first photoelectric sensor 642 detects thedownstream-side edge of the PWB 556, the PWB 556 is decelerated, andwhen the second photoelectric sensor 642 detects the downstream-sideedge of the PWB 556, the PWB 556 is stopped. The arrangement where thestop position of the PWB 556 is differentiated depending upon the typeof the PWB 556 is advantageous in that, for example, the lifetime of theXY robot 568 is prolonged since feed screws 576, 588 are fully utilizedover their entire axial dimensions. It is noted that the PWB supportingdevice and PWB clamp device are disposed such that these devices canrespectively support and clamp the PWB 556, irrespective of the positionof the PWB 556 in the conveying direction. In other words, the stopposition of the PWB 556 is determined within such a range that the PWB556 can be supported by the PWB supporting device and can be clamped bythe PWB clamp device.

In each of the above-described embodiments, the X-axis slide movable inthe X-axis direction which is parallel to the direction in which the PWBconveyor conveys the PWB, holds the Y-axis slide such that the Y-axisslide can move in the Y-axis direction. However, the present inventionmay be embodied (sixth embodiment) such that the relationship of theX-axis and Y-axis slides is inverted, as shown in FIG. 22. Namely, anX-axis slide 656 is held by a Y-axis slide 654 movable in the Y-axisdirection perpendicular to the conveying direction of a PWB conveyor 652in a horizontal plane, such that the X-axis slide 656 is movable in theX-axis direction. The PWB conveyor 652 is disposed on a base 658 suchthat the PWB conveyor 652 conveys the PWB 660 in the conveying directionwhich is the X-axis direction, and has a PWB supporting device 662 whichsupports the PWB 660.

The Y-axis slide 654 is guided by a guide rail 664 (only location ofwhich is indicated by a chain double-dashed line) disposed on the upperportion of the base 658, and moved in the Y-axis direction by a Y-axismoving device (not shown). The guide rail 666 provided on the Y-axisslide 654 holds the X-axis slide 656 such that the X-axis slide 656 ismovable by an X-axis moving device (not shown) in the X-axis direction.A working head similar to that in any one of the above-describedembodiments is disposed on the X-axis slide 656, although it is notshown. For instance, where a component mounting head similar to thecomponent mounting head 230 shown in FIGS. 6 and 7 is employed and acomponent supplying device 20 is disposed on a base 658, anelectronic-circuit-component mounting system as a kind of a workingsystem for a circuit substrate is provided.

Similarly to the above-described embodiments, a PWB detector (not shown)similar to the PWB detector 308 including a first photoelectric sensor310 and a second photoelectric sensor 312 is disposed on the X-axisslide 656, to control the stop position of the PWB 660.

The invention may be otherwise embodied in various forms. For instance,in a case where the circuit substrate is stopped by being brought intocontact with the stopper, the stopper moving apparatus may take the formof a stopper rotating apparatus where a stopper is moved between anoperative position and an inoperative position by rotational motion. Inthis case, the stopper may be held by the Y-axis slide such that thestopper is rotatable around a horizontal axis perpendicular to theconveying direction and is rotated by the stopper rotating apparatusbetween the operative and inoperative positions. Alternatively, thestopper may be rotated around a horizontal axis parallel to theconveying direction.

The substrate detector and stopper may be held by a member which ismovable only in the X-axis direction, such as the X-axis slide in theembodiment shown in FIGS. 1-11. In this case, the substrate detector andstopper are moved only in the direction parallel to the conveyingdirection of the circuit substrate, and the circuit substrate is stoppedat a desired position in the conveying direction.

Further, in the case where the fiducial-mark camera detects thepredetermined detection portion of the PWB to decelerate and then stopthe PWB, the fiducial-mark camera may be adapted to take an image of thepredetermined detection portion when the conveyance is to bedecelerated, and may be adapted to take an image of, and detect, thedownstream-side edge of the PWB in the conveying direction when the PWBis to be stopped.

In addition, in the case where the fiducial-mark camera detects thepredetermined detection portion of the PWB to decelerate and then stopthe PWB, the luminance of the light emitted in the lighting operation bythe lighting device when an image of the predetermined detection portionis taken may be constant whether the image-taking operation is fordeceleration of the PWB or for stopping of the PWB. In such a case, theconstant luminance may be high or low. Moreover, in a circumstance wherethe imaging device can take an image of the PWB without lighting thecircuit substrate, the lighting device may be omitted.

In the case where the circuit substrate is stopped by the stopper, itmay be arranged such that the circuit substrate can be conveyed in bothof the forward and reverse directions. In such a case, the stopper mayconsist of two pairs of stoppers so that the circuit substrate isstopped by an exclusive pair of stoppers for each conveying direction,or alternatively, it may be arranged such that the circuit substrate isstopped by a same single stopper whether the conveying direction isforward or reverse. In either case, the arrival detector consists of twopairs of arrival detectors, to make it possible to detect, irrespectiveof whether the conveyance direction is forward or reverse, the arrivalof the circuit substrate at the position where the circuit substrate isbrought into contact with the stopper.

Further, an end portion of the air cylinder for lifting/lowering thestopper may be utilized as the stopper.

Still further, both of the substrate guides of the substrate conveyormay be a movable guide.

Further, the predetermined detection portion of the circuit substrate isnot limited to the downstream-side edge of the circuit substrate in theconveying direction, but may be other portions of the circuit substrate.

The stop position of the circuit substrate is not limited to the centerposition in the conveying direction but may be other positions.

While the preferred embodiments of the present invention have beendescribed above, for illustrative purpose only, it is to be understoodthat the invention may be embodied with various changes andimprovements, which may occur to those skilled in the art, including themodes described in the part DISCLOSURE OF THE INVENTION in thisspecification.

1-21. (canceled)
 22. A working system for a circuit substrate, comprising: a substrate conveyor which conveys a circuit substrate in a conveying direction along a straight line, and is capable of stopping the circuit substrate at a desired position in the conveying direction; a moving apparatus having a movable member which is movable at least in a direction parallel to the conveying direction of the substrate conveyor, and is capable of moving the movable member to a desired location in the conveying direction; a working head which is held by the movable member and performs a plurality of operations for prescribed points on the circuit substrate which has been stopped; a first detector used for decelerating the circuit substrate and a second detector used for stopping the circuit substrate, which are held by the movable member with a space there between in a direction parallel to the conveying direction and each of which detects a detection portion of the circuit substrate which detection portion is predetermined as an object to be detected, without contacting the detection portion; a substrate stop position controller which controls the moving apparatus to have the first detector and the second detector move to respective predetermined locations, and controls the substrate conveyor such that the substrate conveyor decelerates in response to the detection of the detection portion by the first detector positioned at one of the predetermined locations and stops in response to the detection of the detection portion by the second detector positioned at the other of predetermined locations.
 23. The working system according to claim 22, wherein the substrate stop position controller includes a memory for storing location-related information which relates to a location to which the movable member is moved at least in the direction parallel to the conveying direction for detecting the predetermined detection portion with the first and second detectors.
 24. The working system according to claim 23, wherein the memory includes a portion for storing, as the location-related information, at least one piece of information about at least one of dimensions and a shape of the circuit substrate.
 25. The working system according to claim 23, wherein the memory includes a portion for storing, as the location-related information, at least one piece of information about a direction in which the circuit substrate is conveyed by the substrate conveyor.
 26. The working system according to claim 23, wherein the memory includes a portion for storing, as the location-related information, at least one piece of information for stopping the circuit substrate at the center of the range of movement of the working head moved by the moving apparatus in the conveying direction for the operations to the circuit substrate.
 27. The working system according to claim 23, wherein the memory includes a portion for storing kinds and stop positions of a plurality of kinds of circuit substrates conveyed by the substrate conveyor, such that the stop positions are associated with respectively corresponding kinds of the circuit substrates.
 28. The working system according to claim 22, further including a component supplying device, wherein the working head includes a component mounting head for mounting electronic circuit components supplied from the component supplying device at prescribed points on the circuit substrate which has been stopped at the stop position.
 29. The working system according to claim 28, wherein the component supplying device has a plurality of component feeders, each of which has a component supply portion, contains a multiplicity of electronic circuit components of one kind, and is adapted to sequentially feed the electronic circuit components one by one to the component supply portion, the plurality of component feeders being arranged in a row extending in a direction parallel to the conveying direction of the substrate conveyor.
 30. The working system according to claim 22, wherein the substrate conveyor is a belt conveyor including at least one pair of pulleys, a belt entrained around the at least one pair of pulleys, and a drive assembly which rotates at least one of the at least one pair of pulleys.
 31. The working system according to claim 22, wherein the moving apparatus has: a first movable member which is movable in one of a first direction and a second direction which intersect with each other in a plane parallel to a surface of the circuit substrate which has been conveyed by the substrate conveyor and then stopped; and a second movable member which is held by the first movable member such that the second movable member is movable in the other of the first direction and the second direction and which acts as the movable member holding the working head, the moving apparatus moving the second movable member to a predetermined location in the plane, and the first detector and the second detector being held by one of the first movable member and the second movable member which is movable at least in the direction parallel to the conveying direction.
 32. The working system according to claim 31, wherein the first movable member is movable in the direction parallel to the conveying direction of the substrate conveyor, while the second movable member is movable in a direction perpendicular to the conveying direction.
 33. The working system according to claim 31, wherein the first movable member is movable in a direction perpendicular to the conveying direction, while the second movable member is movable in the direction parallel to the conveying direction.
 34. The working system according to claim 22, wherein each of the first detector and the second detector detects an edge of the circuit substrate on the downstream side in the conveying direction, as the predetermined detection portion.
 35. The working system according to claim 22, wherein each of the first detector and the second detector has a photoelectric sensor including a light emitting element and a light receiving element.
 36. The working system according to claim 35, wherein the photoelectric sensor is of reflection type including a light emitting element and a light receiving element and being configured such that a light radiated from the light emitting element and then reflected by the predetermined detection portion is received by the light receiving element, to detect the predetermined detection portion.
 37. The working system according to claim 24, wherein the memory includes a portion for storing, as the location-related information, at least one piece of information for stopping the circuit substrate at the center of the range of movement of the working head moved by the moving apparatus in the conveying direction for the operations to the circuit substrate.
 38. The working system according to claim 25, wherein the memory includes a portion for storing, as the location-related information, at least one piece of information for stopping the circuit substrate at the center of the range of movement of the working head moved by the moving apparatus in the conveying direction for the operations to the circuit substrate. 